A university is an institution of higher education and research which awards academic degrees in various academic disciplines. Universities provide undergraduate education and postgraduate education; the word university is derived from the Latin universitas magistrorum et scholarium, which means "community of teachers and scholars". While antecedents had existed in Asia and Africa, the modern university system has roots in the European medieval university, created in Italy and evolved from cathedral schools for the clergy during the High Middle Ages; the original Latin word universitas refers in general to "a number of persons associated into one body, a society, community, corporation, etc". At the time of the emergence of urban town life and medieval guilds, specialized "associations of students and teachers with collective legal rights guaranteed by charters issued by princes, prelates, or the towns in which they were located" came to be denominated by this general term. Like other guilds, they were self-regulating and determined the qualifications of their members.
In modern usage the word has come to mean "An institution of higher education offering tuition in non-vocational subjects and having the power to confer degrees," with the earlier emphasis on its corporate organization considered as applying to Medieval universities. The original Latin word referred to degree-awarding institutions of learning in Western and Central Europe, where this form of legal organisation was prevalent, from where the institution spread around the world. An important idea in the definition of a university is the notion of academic freedom; the first documentary evidence of this comes from early in the life of the University of Bologna, which adopted an academic charter, the Constitutio Habita, in 1158 or 1155, which guaranteed the right of a traveling scholar to unhindered passage in the interests of education. Today this is claimed as the origin of "academic freedom"; this is now recognised internationally - on 18 September 1988, 430 university rectors signed the Magna Charta Universitatum, marking the 900th anniversary of Bologna's foundation.
The number of universities signing the Magna Charta Universitatum continues to grow, drawing from all parts of the world. According to Encyclopædia Britannica, the earliest universities were founded in Asia and Africa, predating the first European medieval universities; the University of Al Quaraouiyine, founded in Morocco by Fatima al-Fihri in 859, is considered by some to be the oldest degree-granting university. Their endowment by a prince or monarch and their role in training government officials made early Mediterranean universities similar to Islamic madrasas, although madrasas were smaller, individual teachers, rather than the madrasa itself, granted the license or degree. Scholars like Arnold H. Green and Hossein Nasr have argued that starting in the 10th century, some medieval Islamic madrasas became universities. However, scholars like George Makdisi, Toby Huff and Norman Daniel argue that the European university has no parallel in the medieval Islamic world. Several other scholars consider the university as uniquely European in origin and characteristics.
Darleen Pryds questions this view, pointing out that madaris and European universities in the Mediterranean region shared similar foundations by princely patrons and were intended to provide loyal administrators to further the rulers' agenda. Some scholars, including Makdisi, have argued that early medieval universities were influenced by the madrasas in Al-Andalus, the Emirate of Sicily, the Middle East during the Crusades. Norman Daniel, views this argument as overstated. Roy Lowe and Yoshihito Yasuhara have drawn on the well-documented influences of scholarship from the Islamic world on the universities of Western Europe to call for a reconsideration of the development of higher education, turning away from a concern with local institutional structures to a broader consideration within a global context; the university is regarded as a formal institution that has its origin in the Medieval Christian tradition. European higher education took place for hundreds of years in cathedral schools or monastic schools, in which monks and nuns taught classes.
The earliest universities were developed under the aegis of the Latin Church by papal bull as studia generalia and from cathedral schools. It is possible, that the development of cathedral schools into universities was quite rare, with the University of Paris being an exception, they were founded by Kings or municipal administrations. In the early medieval period, most new universities were founded from pre-existing schools when these schools were deemed to have become sites of higher education. Many historians state that universities and cathedral schools were a continuation of the interest in learning promoted by The residence of a religious community. Pope Gregory VII was critical in promoting and regulating the concept of modern university as his 1079 Papal Decree ordered the regulated establishment of cathedral schools that transformed themselves into the first European universities; the first universities in Europe with a form of corporate/guild structure were the University of Bologna, the University of Paris, the University of Oxford.
The University of Bologna began as a law school teach
Bolivia the Plurinational State of Bolivia is a landlocked country located in western-central South America. The capital is Sucre; the largest city and principal industrial center is Santa Cruz de la Sierra, located on the Llanos Orientales a flat region in the east of Bolivia. The sovereign state of Bolivia is a constitutionally unitary state, divided into nine departments, its geography varies from the peaks of the Andes in the West, to the Eastern Lowlands, situated within the Amazon Basin. It is bordered to the north and east by Brazil, to the southeast by Paraguay, to the south by Argentina, to the southwest by Chile, to the northwest by Peru. One-third of the country is within the Andean mountain range. With 1,098,581 km2 of area, Bolivia is the fifth largest country in South America, the 27th largest in the world and the largest landlocked country in the Southern Hemisphere; the country's population, estimated at 11 million, is multiethnic, including Amerindians, Europeans and Africans.
The racial and social segregation that arose from Spanish colonialism has continued to the modern era. Spanish is the official and predominant language, although 36 indigenous languages have official status, of which the most spoken are Guarani and Quechua languages. Before Spanish colonization, the Andean region of Bolivia was part of the Inca Empire, while the northern and eastern lowlands were inhabited by independent tribes. Spanish conquistadors arriving from Cuzco and Asunción took control of the region in the 16th century. During the Spanish colonial period Bolivia was administered by the Royal Audiencia of Charcas. Spain built its empire in large part upon the silver, extracted from Bolivia's mines. After the first call for independence in 1809, 16 years of war followed before the establishment of the Republic, named for Simón Bolívar. Over the course of the 19th and early 20th century Bolivia lost control of several peripheral territories to neighboring countries including the seizure of its coastline by Chile in 1879.
Bolivia remained politically stable until 1971, when Hugo Banzer led a coup d'état which replaced the socialist government of Juan José Torres with a military dictatorship headed by Banzer. Banzer's regime cracked down on leftist and socialist opposition and other forms of dissent, resulting in the torture and deaths of a number of Bolivian citizens. Banzer was ousted in 1978 and returned as the democratically elected president of Bolivia from 1997 to 2001. Modern Bolivia is a charter member of the UN, IMF, NAM, OAS, ACTO, Bank of the South, ALBA and USAN. For over a decade Bolivia has had one of the highest economic growth rates in Latin America, it is a developing country, with a medium ranking in the Human Development Index, a poverty level of 38.6%, one of the lowest crime rates in Latin America. Its main economic activities include agriculture, fishing and manufacturing goods such as textiles, refined metals, refined petroleum. Bolivia is rich in minerals, including tin and lithium. Bolivia is named after Simón Bolívar, a Venezuelan leader in the Spanish American wars of independence.
The leader of Venezuela, Antonio José de Sucre, had been given the option by Bolívar to either unite Charcas with the newly formed Republic of Peru, to unite with the United Provinces of Rio de la Plata, or to formally declare its independence from Spain as a wholly independent state. Sucre opted to create a brand new state and on 6 August 1825, with local support, named it in honor of Simón Bolívar; the original name was Republic of Bolívar. Some days congressman Manuel Martín Cruz proposed: "If from Romulus comes Rome from Bolívar comes Bolivia"; the name was approved by the Republic on 3 October 1825. In 2009, a new constitution changed the country's official name to "Plurinational State of Bolivia" in recognition of the multi-ethnic nature of the country and the enhanced position of Bolivia's indigenous peoples under the new constitution; the region now known as Bolivia had been occupied for over 2,500 years. However, present-day Aymara associate themselves with the ancient civilization of the Tiwanaku culture which had its capital at Tiwanaku, in Western Bolivia.
The capital city of Tiwanaku dates from as early as 1500 BC when it was a small, agriculturally based village. The community grew to urban proportions between AD 600 and AD 800, becoming an important regional power in the southern Andes. According to early estimates, the city covered 6.5 square kilometers at its maximum extent and had between 15,000 and 30,000 inhabitants. In 1996 satellite imaging was used to map the extent of fossilized suka kollus across the three primary valleys of Tiwanaku, arriving at population-carrying capacity estimates of anywhere between 285,000 and 1,482,000 people. Around AD 400, Tiwanaku went from being a locally dominant force to a predatory state. Tiwanaku expanded its reaches into the Yungas and brought its culture and way of life to many other cultures in Peru and Chile. Tiwanaku was not a violent culture in many respects. In order to expand its reach, Tiwanaku exercised great political astuteness, creating colonies, fostering trade agree
The Argentine Army is the land armed force branch of the Armed Forces of the Argentine Republic and the senior military service of the country. Under the Argentine Constitution, the President of Argentina is the Commander-in-Chief of the Armed Forces, exercising his or her command authority through the Minister of Defense; the Army's official foundation date is May 29, 1810, four days after the Spanish colonial administration in Buenos Aires was overthrown. The new national army was formed out of several pre-existent colonial militia units and locally manned regiments; as of 2018, the active element of the Argentine Army numbered some 51,309 military personnel. Several armed expeditions were sent to the Upper Peru, Paraguay and Chile to fight Spanish forces and secure Argentina's newly gained independence; the most famous of these expeditions was the one led by General José de San Martín, who led a 5000-man army across the Andes Mountains to expel the Spaniards from Chile and from Perú. While the other expeditions failed in their goal of bringing all the dependencies of the former Viceroyalty of the Río de la Plata under the new government in Buenos Aires, they prevented the Spaniards from crushing the rebellion.
During the civil wars of the first half of the 19th century, the Argentine Army became fractionalized under the leadership of the so-called caudillos, provincial leaders who waged a war against the centralist Buenos Aires administration. However, the Army was re-unified during the war with the Brazilian Empire.. It was only with the establishment of a Constitution and a national government recognized by all the provinces that the Army became a single force, absorbing the older provincial militias; the Army went on to fight the War of the Triple Alliance in the 1860s together with Brazil and Uruguay against Paraguay. After that war, the Army became involved in Argentina's Conquista del Desierto: the campaign to occupy Patagonia and root out the natives, who conducted looting raids throughout the country. Between 1880 and 1930, the Army sought to become a professional force without active involvement in politics though many a political figure -President Julio Argentino Roca, for example- benefitted from a past military career.
The Army prevented the fall of the government in a number of Radical-led uprisings. Meanwhile, the military in general and the Army, in particular, contributed to develop Argentina's unsettled southern frontier and its nascent industrial complex; the main foreign influence during this period was, by and large, the Prussian doctrine. Because of that, during both World Wars most of the officers supported the Germans, more or less while the Argentine Navy favored the British instead. In 1930, a small group of Army forces deposed President Hipólito Yrigoyen without much response from the rest of the Army and the Navy; this was the beginning of a long history of political intervention by the military. Another coup, in 1943, was responsible for bringing an obscure colonel into the political limelight: Juan Perón. Though Perón had the support of the military during his two consecutive terms of office, his repressive government alienated many officers, which led to a military uprising which overthrew him in September 1955.
Between 1955 and 1973 the Army and the rest of the military became vigilant over the possible re-emergence of Peronism in the political arena, which led to two new coups against elected Presidents in 1962 and 1966. It should be noted that political infighting eroded discipline and cohesion within the army, to the extent that there was armed fighting between contending military units during the early 1960s; the military government which ruled Argentina between 1966 and 1973 saw the growing activities of groups such as Montoneros and the ERP, a important social movement. During Héctor Cámpora's first months of government, a rather moderate and left-wing Peronist, approximatively 600 social conflicts and factory occupations had taken place. Following the June 20, 1973 Ezeiza massacre and right-wing Peronism broke apart, while the Triple A death squad, organized by José López Rega, closest advisor to María Estela Martínez de Perón, started a campaign of assassinations against left-wing opponents.
But Isabel Perón herself was ousted during the March 1976 coup by a military junta. The new military government, self-named Proceso de Reorganización Nacional, put a stop to the guerrilla's campaigns, but soon it became known that violent methods and severe violations of human rights had taken place, in what the dictatorship called a "Dirty War" — a term refused by jurists during the 1985 Trial of the Juntas. Batallón de Inteligencia 601 became infamous during this period, it was a special military intelligence service set up in the late 1970s, active in the Dirty War and Operation Condor, disbanded in 2000. Its personnel collected information on and infiltrated guerrilla groups and human rights organisations, coordinated killings and other abuses; the unit participated in the training of Nicaraguan Contras with US assistance, including from John Negroponte. Meanwhile, the Guevarist People's Revolutionary Army, led by Roberto Santucho and inspired by Che Guevara's foco theory, began a rural insurgency in the province of Tucumán, in the mountainous n
Argentina the Argentine Republic, is a country located in the southern half of South America. Sharing the bulk of the Southern Cone with Chile to the west, the country is bordered by Bolivia and Paraguay to the north, Brazil to the northeast and the South Atlantic Ocean to the east, the Drake Passage to the south. With a mainland area of 2,780,400 km2, Argentina is the eighth-largest country in the world, the fourth largest in the Americas, the largest Spanish-speaking nation; the sovereign state is subdivided into twenty-three provinces and one autonomous city, Buenos Aires, the federal capital of the nation as decided by Congress. The provinces and the capital exist under a federal system. Argentina claims sovereignty over part of Antarctica, the Falkland Islands, South Georgia and the South Sandwich Islands; the earliest recorded human presence in modern-day Argentina dates back to the Paleolithic period. The Inca Empire expanded to the northwest of the country in Pre-Columbian times; the country has its roots in Spanish colonization of the region during the 16th century.
Argentina rose as the successor state of the Viceroyalty of the Río de la Plata, a Spanish overseas viceroyalty founded in 1776. The declaration and fight for independence was followed by an extended civil war that lasted until 1861, culminating in the country's reorganization as a federation of provinces with Buenos Aires as its capital city; the country thereafter enjoyed relative peace and stability, with several waves of European immigration radically reshaping its cultural and demographic outlook. The almost-unparalleled increase in prosperity led to Argentina becoming the seventh wealthiest nation in the world by the early 20th century. Following the Great Depression in the 1930s, Argentina descended into political instability and economic decline that pushed it back into underdevelopment, though it remained among the fifteen richest countries for several decades. Following the death of President Juan Perón in 1974, his widow, Isabel Martínez de Perón, ascended to the presidency, she was overthrown in 1976 by a U.
S.-backed coup which installed a right-wing military dictatorship. The military government persecuted and murdered numerous political critics and leftists in the Dirty War, a period of state terrorism that lasted until the election of Raúl Alfonsín as President in 1983. Several of the junta's leaders were convicted of their crimes and sentenced to imprisonment. Argentina is a prominent regional power in the Southern Cone and Latin America, retains its historic status as a middle power in international affairs. Argentina has the second largest economy in South America, the third-largest in Latin America, membership in the G-15 and G-20 major economies, it is a founding member of the United Nations, World Bank, World Trade Organization, Union of South American Nations, Community of Latin American and Caribbean States and the Organization of Ibero-American States. Despite its history of economic instability, it ranks second highest in the Human Development Index in Latin America; the description of the country by the word Argentina has been found on a Venetian map in 1536.
In English the name "Argentina" comes from the Spanish language, however the naming itself is not Spanish, but Italian. Argentina means in Italian " of silver, silver coloured" borrowed from the Old French adjective argentine " of silver" > "silver coloured" mentioned in the 12th century. The French word argentine is the feminine form of argentin and derives from argent "silver" with the suffix -in; the Italian naming "Argentina" for the country implies Terra Argentina "land of silver" or Costa Argentina "coast of silver". In Italian, the adjective or the proper noun is used in an autonomous way as a substantive and replaces it and it is said l'Argentina; the name Argentina was first given by the Venetian and Genoese navigators, such as Giovanni Caboto. In Spanish and Portuguese, the words for "silver" are plata and prata and " of silver" is said plateado and prateado. Argentina was first associated with the silver mountains legend, widespread among the first European explorers of the La Plata Basin.
The first written use of the name in Spanish can be traced to La Argentina, a 1602 poem by Martín del Barco Centenera describing the region. Although "Argentina" was in common usage by the 18th century, the country was formally named "Viceroyalty of the Río de la Plata" by the Spanish Empire, "United Provinces of the Río de la Plata" after independence; the 1826 constitution included the first use of the name "Argentine Republic" in legal documents. The name "Argentine Confederation" was commonly used and was formalized in the Argentine Constitution of 1853. In 1860 a presidential decree settled the country's name as "Argentine Republic", that year's constitutional amendment ruled all the names since 1810 as valid. In the English language the country was traditionally called "the Argentine", mimicking the typical Spanish usage la Argentina and resulting from a mistaken shortening of the fuller name'Argentine Republic'.'The Argentine' fell out of fashion during the mid-to-late 20th century, now the country is referred to as "Argentina".
In the Spanish language "Argentina" is feminine, taking the feminine article "La" as the i
Brazil the Federative Republic of Brazil, is the largest country in both South America and Latin America. At 8.5 million square kilometers and with over 208 million people, Brazil is the world's fifth-largest country by area and the fifth most populous. Its capital is Brasília, its most populated city is São Paulo; the federation is composed of the union of the 26 states, the Federal District, the 5,570 municipalities. It is the largest country to have Portuguese as an official language and the only one in the Americas. Bounded by the Atlantic Ocean on the east, Brazil has a coastline of 7,491 kilometers, it borders all other South American countries except Ecuador and Chile and covers 47.3% of the continent's land area. Its Amazon River basin includes a vast tropical forest, home to diverse wildlife, a variety of ecological systems, extensive natural resources spanning numerous protected habitats; this unique environmental heritage makes Brazil one of 17 megadiverse countries, is the subject of significant global interest and debate regarding deforestation and environmental protection.
Brazil was inhabited by numerous tribal nations prior to the landing in 1500 of explorer Pedro Álvares Cabral, who claimed the area for the Portuguese Empire. Brazil remained a Portuguese colony until 1808, when the capital of the empire was transferred from Lisbon to Rio de Janeiro. In 1815, the colony was elevated to the rank of kingdom upon the formation of the United Kingdom of Portugal and the Algarves. Independence was achieved in 1822 with the creation of the Empire of Brazil, a unitary state governed under a constitutional monarchy and a parliamentary system; the ratification of the first constitution in 1824 led to the formation of a bicameral legislature, now called the National Congress. The country became a presidential republic in 1889 following a military coup d'état. An authoritarian military junta came to power in 1964 and ruled until 1985, after which civilian governance resumed. Brazil's current constitution, formulated in 1988, defines it as a democratic federal republic. Due to its rich culture and history, the country ranks thirteenth in the world by number of UNESCO World Heritage Sites.
Brazil is considered an advanced emerging economy. It has the ninth largest GDP in the world by nominal, eight and PPP measures, it is one of the world's major breadbaskets, being the largest producer of coffee for the last 150 years. It is classified as an upper-middle income economy by the World Bank and a newly industrialized country, with the largest share of global wealth in Latin America. Brazil is a regional power and sometimes considered a great or a middle power in international affairs. On account of its international recognition and influence, the country is subsequently classified as an emerging power and a potential superpower by several analysts. Brazil is a founding member of the United Nations, the G20, BRICS, Union of South American Nations, Organization of American States, Organization of Ibero-American States and the Community of Portuguese Language Countries, it is that the word "Brazil" comes from the Portuguese word for brazilwood, a tree that once grew plentifully along the Brazilian coast.
In Portuguese, brazilwood is called pau-brasil, with the word brasil given the etymology "red like an ember", formed from brasa and the suffix -il. As brazilwood produces a deep red dye, it was valued by the European textile industry and was the earliest commercially exploited product from Brazil. Throughout the 16th century, massive amounts of brazilwood were harvested by indigenous peoples along the Brazilian coast, who sold the timber to European traders in return for assorted European consumer goods; the official Portuguese name of the land, in original Portuguese records, was the "Land of the Holy Cross", but European sailors and merchants called it the "Land of Brazil" because of the brazilwood trade. The popular appellation eclipsed and supplanted the official Portuguese name; some early sailors called it the "Land of Parrots". In the Guarani language, an official language of Paraguay, Brazil is called "Pindorama"; this was the name the indigenous population gave to the region, meaning "land of the palm trees".
Some of the earliest human remains found in the Americas, Luzia Woman, were found in the area of Pedro Leopoldo, Minas Gerais and provide evidence of human habitation going back at least 11,000 years. The earliest pottery found in the Western Hemisphere was excavated in the Amazon basin of Brazil and radiocarbon dated to 8,000 years ago; the pottery was found near Santarém and provides evidence that the tropical forest region supported a complex prehistoric culture. The Marajoara culture flourished on Marajó in the Amazon delta from 800 CE to 1400 CE, developing sophisticated pottery, social stratification, large populations, mound building, complex social formations such as chiefdoms. Around the time of the Portuguese arrival, the territory of current day Brazil had an estimated indigenous population of 7 million people semi-nomadic who subsisted on hunting, fishing and migrant agriculture; the indigenous population of Brazil comprised several large indigenous ethnic groups. The Tupí people were subdivided into the Tupiniquins and Tupinambás, there were many subdivisions of the other gro
A hospital is a health care institution providing patient treatment with specialized medical and nursing staff and medical equipment. The best-known type of hospital is the general hospital, which has an emergency department to treat urgent health problems ranging from fire and accident victims to a sudden illness. A district hospital is the major health care facility in its region, with a large number of beds for intensive care and additional beds for patients who need long-term care. Specialized hospitals include trauma centers, rehabilitation hospitals, children's hospitals, seniors' hospitals, hospitals for dealing with specific medical needs such as psychiatric treatment and certain disease categories. Specialized hospitals can help reduce health care costs compared to general hospitals. Hospitals are classified as general, specialty, or government depending on the sources of income received. A teaching hospital combines assistance to people with teaching to medical nurses; the medical facility smaller than a hospital is called a clinic.
Hospitals have a range of departments and specialist units such as cardiology. Some hospitals have outpatient departments and some have chronic treatment units. Common support units include a pharmacy and radiology. Hospitals are funded by the public sector, health organisations, health insurance companies, or charities, including direct charitable donations. Hospitals were founded and funded by religious orders, or by charitable individuals and leaders. Hospitals are staffed by professional physicians, surgeons and allied health practitioners, whereas in the past, this work was performed by the members of founding religious orders or by volunteers. However, there are various Catholic religious orders, such as the Alexians and the Bon Secours Sisters that still focus on hospital ministry in the late 1990s, as well as several other Christian denominations, including the Methodists and Lutherans, which run hospitals. In accordance with the original meaning of the word, hospitals were "places of hospitality", this meaning is still preserved in the names of some institutions such as the Royal Hospital Chelsea, established in 1681 as a retirement and nursing home for veteran soldiers.
During the Middle Ages, hospitals served different functions from modern institutions. Middle Ages hospitals were hostels for pilgrims, or hospital schools; the word "hospital" comes from the Latin hospes, signifying a foreigner, hence a guest. Another noun derived from this, hospitium came to signify hospitality, the relation between guest and shelterer, hospitality and hospitable reception. By metonymy the Latin word came to mean a guest-chamber, guest's lodging, an inn. Hospes is thus the root for the English words host hospitality, hospice and hotel; the latter modern word derives from Latin via the ancient French romance word hostel, which developed a silent s, which letter was removed from the word, the loss of, signified by a circumflex in the modern French word hôtel. The German word'Spital' shares similar roots; the grammar of the word differs depending on the dialect. In the United States, hospital requires an article; some patients go to a hospital just for diagnosis, treatment, or therapy and leave without staying overnight.
Hospitals are distinguished from other types of medical facilities by their ability to admit and care for inpatients whilst the others, which are smaller, are described as clinics. The best-known type of hospital is the general hospital known as an acute-care hospital; these facilities handle many kinds of disease and injury, have an emergency department or trauma center to deal with immediate and urgent threats to health. Larger cities may have several hospitals of facilities; some hospitals in the United States and Canada, have their own ambulance service. A district hospital is the major health care facility in its region, with large numbers of beds for intensive care, critical care, long-term care. In California, "district hospital" refers to a class of healthcare facility created shortly after World War II to address a shortage of hospital beds in many local communities. Today, district hospitals are the sole public hospitals in 19 of California's counties, are the sole locally-accessible hospital within nine additional counties in which one or more other hospitals are present at substantial distance from a local community.
Twenty-eight of California's rural hospitals and 20 of its critical-access hospitals are district hospitals. They are formed by local municipalities, have boards that are individually elected by their local communities, exist to serve local needs, they are a important provider of healthcare to uninsured patients and patients with Medi-Cal. In 2012, district hospitals provided $54 million in uncompensated care in California. Types of specialised hospitals incl
The Americas comprise the totality of the continents of North and South America. Together, they comprise the New World. Along with their associated islands, they cover 8% of Earth's total surface area and 28.4% of its land area. The topography is dominated by the American Cordillera, a long chain of mountains that runs the length of the west coast; the flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, St. Lawrence River / Great Lakes basin, La Plata. Since the Americas extend 14,000 km from north to south, the climate and ecology vary from the arctic tundra of Northern Canada and Alaska, to the tropical rain forests in Central America and South America. Humans first settled the Americas from Asia between 17,000 years ago. A second migration of Na-Dene speakers followed from Asia; the subsequent migration of the Inuit into the neoarctic around 3500 BCE completed what is regarded as the settlement by the indigenous peoples of the Americas. The first known European settlement in the Americas was by the Norse explorer Leif Erikson.
However, the colonization never became permanent and was abandoned. The Spanish voyages of Christopher Columbus from 1492 to 1502 resulted in permanent contact with European powers, which led to the Columbian exchange and inaugurated a period of exploration and colonization whose effects and consequences persist to the present. Diseases introduced from Europe and West Africa devastated the indigenous peoples, the European powers colonized the Americas. Mass emigration from Europe, including large numbers of indentured servants, importation of African slaves replaced the indigenous peoples. Decolonization of the Americas began with the American Revolution in the 1770s and ended with the Spanish–American War in the late 1890s. All of the population of the Americas resides in independent countries; the Americas are home to over a billion inhabitants, two-thirds of which reside in the United States, Brazil, or Mexico. It is home to eight megacities: New York City, Mexico City, São Paulo, Los Angeles, Buenos Aires, Rio de Janeiro, Bogotá, Lima.
The name America was first recorded in 1507. Christie's auction house says a two-dimensional globe created by Martin Waldseemüller was the earliest recorded use of the term; the name was used in the Cosmographiae Introductio written by Matthias Ringmann, in reference to South America. It was applied to both North and South America by Gerardus Mercator in 1538. America derives from the Latin version of Italian explorer Amerigo Vespucci's first name; the feminine form America accorded with the feminine names of Asia and Europa. In modern English and South America are considered separate continents, taken together are called America or the Americas in the plural; when conceived as a unitary continent, the form is the continent of America in the singular. However, without a clarifying context, singular America in English refers to the United States of America. In the English-speaking world, the term America used to refer to a single continent until the 1950s: According to historians Kären Wigen and Martin W. Lewis, While it might seem surprising to find North and South America still joined into a single continent in a book published in the United States in 1937, such a notion remained common until World War II.
By the 1950s, however all American geographers had come to insist that the visually distinct landmasses of North and South America deserved separate designations. This shift did not seem to happen in Romance-speaking countries, where America is still considered a continent encompassing the North America and South America subcontinents, as well as Central America; the first inhabitants migrated into the Americas from Asia. Habitation sites are known in Alaska and the Yukon from at least 20,000 years ago, with suggested ages of up to 40,000 years. Beyond that, the specifics of the Paleo-Indian migration to and throughout the Americas, including the dates and routes traveled, are subject to ongoing research and discussion. Widespread habitation of the Americas occurred during the late glacial maximum, from 16,000 to 13,000 years ago; the traditional theory has been that these early migrants moved into the Beringia land bridge between eastern Siberia and present-day Alaska around 40,000–17,000 years ago, when sea levels were lowered during the Quaternary glaciation.
These people are believed to have followed herds of now-extinct pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using primitive boats, they migrated down the Pacific coast to South America. Evidence of the latter would since have been covered by a sea level rise of hundreds of meters following the last ice age. Both routes may have