An endorheic basin is a limited drainage basin that retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but converges instead into lakes or swamps, permanent or seasonal, that equilibrate through evaporation. Such a basin may be referred to as a closed or terminal basin or as an internal drainage system or interior drainage basin. Endorheic regions, in contrast to exorheic regions, which flow to the ocean in geologically defined patterns, are closed hydrologic systems, their surface waters drain to inland terminal locations where the water evaporates or seeps into the ground, having no access to discharge into the sea. Endorheic water bodies include some of the largest lakes in the world, such as the Caspian Sea, the world's largest saline inland sea. Endorheic basins constitute local base levels, defining a limit of erosion and deposition processes of nearby areas; the term comes from the Ancient Greek: ἔνδον, éndon, "within" and ῥεῖν, rheîn, "to flow".
Endorheic lakes are bodies of water. Most of the water falling on Earth finds its way to the oceans through a network of rivers and wetlands. However, there is a class of water bodies that are located in closed or endorheic watersheds where the topography prevents their drainage to the oceans; these endorheic watersheds are called terminal lakes or sink lakes. Endorheic lakes are in the interior of a landmass, far from an ocean in areas of low rainfall, their watersheds are confined by natural geologic land formations such as a mountain range, cutting off water egress to the ocean. The inland water flows into dry watersheds where the water evaporates, leaving a high concentration of minerals and other inflow erosion products. Over time this input of erosion products can cause the endorheic lake to become saline. Since the main outflow pathways of these lakes are chiefly through evaporation and seepage, endorheic lakes are more sensitive to environmental pollutant inputs than water bodies that have access to oceans, as pollution can be trapped in them and accumulate over time.
Endorheic regions can occur in any climate but are most found in desert locations. In areas where rainfall is higher, riparian erosion will carve drainage channels, or cause the water level in the terminal lake to rise until it finds an outlet, breaking the enclosed endorheic hydrological system's geographical barrier and opening it to the surrounding terrain; the Black Sea was such a lake, having once been an independent hydrological system before the Mediterranean Sea broke through the terrain separating the two. Lake Bonneville was another such lake; the Malheur/Harney lake system in Oregon is cut off from drainage to the ocean, but has an outflow channel to the Malheur River, dry, but flows in years of peak precipitation. Examples of humid regions in endorheic basins exist at high elevation; these regions are subject to substantial flooding in wet years. The area containing Mexico City is one such case, with annual precipitation of 850 mm and characterized by waterlogged soils that require draining.
Endorheic regions tend to be far inland with their boundaries defined by mountains or other geological features that block their access to oceans. Since the inflowing water can evacuate only through seepage or evaporation, dried minerals or other products collect in the basin making the water saline and making the basin vulnerable to pollution. Continents vary in their concentration of endorheic regions due to conditions of geography and climate. Australia has the highest percentage of endorheic regions at 21 percent while North America has the least at five percent. 18 percent of the earth's land drains to endorheic lakes or seas, the largest of these land areas being the interior of Asia. In deserts, water inflow is low and loss to solar evaporation high, drastically reducing the formation of complete drainage systems. Closed water flow areas lead to the concentration of salts and other minerals in the basin. Minerals leached from the surrounding rocks are deposited in the basin, left behind when the water evaporates.
Thus endorheic basins contain extensive salt pans. These areas tend to be large, flat hardened surfaces and are sometimes used for aviation runways or land speed record attempts, because of their extensive areas of level terrain. Both permanent and seasonal endorheic lakes can form in endorheic basins; some endorheic basins are stable, climate change having reduced precipitation to the degree that a lake no longer forms. Most permanent endorheic lakes change size and shape over time becoming much smaller or breaking into several smaller parts during the dry season; as humans have expanded into uninhabitable desert areas, the river systems that feed many endorheic lakes have been altered by the construction of dams and aqueducts. As a result, many endorheic lakes in developed or developing countries have contracted resulting in increased salinity, higher concentrations of pollutants, the disruption of ecosystems. Within exorheic basins, there can be "non-contributing", low-lying areas that trap runoff and prevent it from contributing to flows downstream during years of average or below-average runoff.
In flat river basins, non-contributing areas can be a large fraction of the river
Tenochtitlan known as Mexica-Tenochtitlan, was a large Mexica city-state in what is now the center of Mexico City. The exact date of the founding of the city is unclear, but the most accepted date is March 13, 1325; the city was built on an island in what was Lake Texcoco in the Valley of Mexico. The city was the capital of the expanding Aztec Empire in the 15th century until it was captured by the Spanish in 1521. At its peak, it was the largest city in the pre-Columbian Americas, it subsequently became a cabecera of the Viceroyalty of New Spain. Today, the ruins of Tenochtitlan are in the historic center of the Mexican capital; the World Heritage Site of Xochimilco contains. Tenochtitlan was one of two Mexica āltēpetl on the other being Tlatelolco. Traditionally, the name Tenochtitlan was thought to come from Nahuatl tetl and nōchtli and is thought to mean, "Among the prickly pears rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggest the second vowel was short, so that the true etymology remains uncertain.
Tenochtitlan covered an estimated 8 to 13.5 km2, situated on the western side of the shallow Lake Texcoco. At the time of Spanish conquests, Mexico City comprised both Tlatelolco; the city extended from north to south, from the north border of Tlatelolco to the swamps, which by that time were disappearing to the west. The city was connected to the mainland by bridges and causeways leading to the north and west; the causeways were interrupted by bridges that allowed canoes and other water traffic to pass freely. The bridges could be pulled away, to defend the city; the city was interlaced with a series of canals, so that all sections of the city could be visited either on foot or via canoe. Lake Texcoco was the largest of five interconnected lakes. Since it formed in an endorheic basin, Lake Texcoco was brackish. During the reign of Moctezuma I, the "levee of Nezahualcoyotl" was constructed, reputedly designed by Nezahualcoyotl. Estimated to be 12 to 16 km in length, the levee was completed circa 1453.
The levee kept fresh spring-fed water in the waters around Tenochtitlan and kept the brackish waters beyond the dike, to the east. Two double aqueducts, each more than 4 km long and made of terracotta, provided the city with fresh water from the springs at Chapultepec; this was intended for cleaning and washing. For drinking, water from mountain springs was preferred. Most of the population liked to bathe twice a day. According to the context of Aztec culture in literature, the soap that they most used was the root of a plant called copalxocotl, to clean their clothes they used the root of metl; the upper classes and pregnant women washed themselves in a temāzcalli, similar to a sauna bath, still used in the south of Mexico. This was popular in other Mesoamerican cultures; when we saw so many cities and villages built in the water and other great towns on dry land we were amazed and said that it was like the enchantments on account of the great towers and cues and buildings rising from the water, all built of masonry.
And some of our soldiers asked whether the things that we saw were not a dream? I do not know how to describe it, seeing things as we did that had never been heard of or seen before, not dreamed about; the city was divided into camps. There were three main streets that crossed the city, each leading to one of the three causeways to the mainland of Tepeyac and Tlacopan. Modern names please. Bernal Díaz del Castillo reported. Surrounding the raised causeways were artificial floating gardens with canal waterways and gardens of plants and trees; the calpullis were divided by channels used for transportation, with wood bridges that were removed at night. The earliest European images of the city were woodcuts published in Augsburg around 1522; each calpulli had its own tiyanquiztli, but there was a main marketplace in Tlatelolco – Tenochtitlan's sister city. Cortés estimated it was twice the size of the city of Salamanca with about 60,000 people trading daily. Bernardino de Sahagún provides a more conservative population estimate of 20,000 on ordinary days and 40,000 on feast days.
There were specialized markets in the other central Mexican cities. In the center of the city were the public buildings and palaces. Inside a walled square, 500 meters to a side, was the ceremonial center. There were about 45 public buildings, including: the Templo Mayor, dedicated to the Aztec patron deity Huitzilopochtli and the Rain God Tlaloc. Outside was the palace of Moctezum
An islet is a small island. As suggested by its origin as islette, an Old French diminutive of "isle", use of the term implies small size, but little attention is given to drawing an upper limit on its applicability. Cay or Key – an islet formed by the accumulation of fine sand deposits atop a reef. Motu – A reef islet formed by broken coral and sand, surrounding an atoll. River island – A small islet within the current of a river. Rock – A "rock", in the sense of a type of islet, is an uninhabited landform composed of rock, lying offshore, having at most minimal vegetation. Sandbar – An exposed sandbar is another type of islet. Sea stack – A thin, vertical landform jutting out of a body of water. Skerry – A small rocky island defined to be too small for habitation. Subsidiary islets – A more technical application is to small land features, isolated by water, lying off the shore of a larger island. Any emergent land in an atoll is called an islet. Tidal island – Often small islands which lie off the mainland of an area, being connected to it in low tide and isolated in high tide.
In the Caribbean and West Atlantic, islets are called cays or keys. Rum Cay in the Bahamas and the Florida Keys off Florida are examples of islets. In Normandy and the Channel Islands, they are identified by the French suffix -hou from the Scandinavian -holm. In Scotland and Ireland, they are called inches, from the Gaelic innis, which meant island, but has been supplanted to refer to smaller islands. In Ireland they are termed skerries. In and around Polynesia, islets are known by the term motu, from the term for the coral-rubble islets common to the region. In and around the River Thames in England, small islands are known as eyots. Whether an islet is considered a rock or not can have significant economic consequences under Article 121 of the UN Convention on the Law of the Sea, which stipulates that "Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf." One long-term dispute over the status of such an islet was that of Snake Island.
The International Court of Justice jurisprudence however sometimes ignores islets, regardless of inhabitation status, in deciding territorial disputes. There are thousands of islets on Earth: 24,000 islands and islets in the Stockholm archipelago alone; the following is a list of example islets from around the world. Clive Schofield. "Islands or Rocks, Is that the Real Question? The Treatment of Islands in the Delimitation of Maritime Boundaries". In Myron H. Nordquist, John Norton Moore, Alfred H. A. Soons, Hak-So Kim; the Law of the Sea Convention: US Accession and Globalization. Martinus Nijhoff Publishers. Pp. 322–340. ISBN 978-90-04-20136-1. CS1 maint: Uses editors parameter
Last Glacial Period
The Last Glacial Period occurred from the end of the Eemian interglacial to the end of the Younger Dryas, encompassing the period c. 115,000 – c. 11,700 years ago. This most recent glacial period is part of a larger pattern of glacial and interglacial periods known as the Quaternary glaciation extending from c. 2,588,000 years ago to present. The definition of the Quaternary as beginning 2.58 Ma is based on the formation of the Arctic ice cap. The Antarctic ice sheet began to form earlier, in the mid-Cenozoic; the term Late Cenozoic Ice Age is used to include this early phase. During this last glacial period there were alternating episodes of glacier retreat. Within the last glacial period the Last Glacial Maximum was 22,000 years ago. While the general pattern of global cooling and glacier advance was similar, local differences in the development of glacier advance and retreat make it difficult to compare the details from continent to continent. 13,000 years ago, the Late Glacial Maximum began.
The end of the Younger Dryas about 11,700 years ago marked the beginning of the Holocene geological epoch, which includes the Holocene glacial retreat. From the point of view of human archaeology, the last glacial period falls in the Paleolithic and early Mesolithic periods; when the glaciation event started, Homo sapiens were confined to lower latitudes and used tools comparable to those used by Neanderthals in western and central Eurasia and by Homo erectus in Asia. Near the end of the event, Homo sapiens migrated into Australia. Archaeological and genetic data suggest that the source populations of Paleolithic humans survived the last glacial period in sparsely wooded areas and dispersed through areas of high primary productivity while avoiding dense forest cover; the last glacial period is sometimes colloquially referred to as the "last ice age", though this use is incorrect because an ice age is a longer period of cold temperature in which year-round ice sheets are present near one or both poles.
Glacials are colder phases within an ice age. Thus, the end of the last glacial period, about 11,700 years ago, is not the end of the last ice age since extensive year-round ice persists in Antarctica and Greenland. Over the past few million years the glacial-interglacial cycles have been "paced" by periodic variations in the Earth's orbit via Milankovitch cycles; the last glacial period is the best-known part of the current ice age, has been intensively studied in North America, northern Eurasia, the Himalaya and other glaciated regions around the world. The glaciations that occurred during this glacial period covered many areas in the Northern Hemisphere and to a lesser extent in the Southern Hemisphere, they have different names developed and depending on their geographic distributions: Fraser, Wisconsinan or Wisconsin, Midlandian, Würm, Mérida, Weichselian or Vistulian, Valdai in Russia and Zyryanka in Siberia, Llanquihue in Chile, Otira in New Zealand. The geochronological Late Pleistocene includes the late glacial and the preceding penultimate interglacial period.
Canada was nearly covered by ice, as well as the northern part of the United States, both blanketed by the huge Laurentide Ice Sheet. Alaska remained ice free due to arid climate conditions. Local glaciations existed in the Rocky Mountains and the Cordilleran Ice Sheet and as ice fields and ice caps in the Sierra Nevada in northern California. In Britain, mainland Europe, northwestern Asia, the Scandinavian ice sheet once again reached the northern parts of the British Isles, Germany and Russia, extending as far east as the Taymyr Peninsula in western Siberia; the maximum extent of western Siberian glaciation was reached by 16,000–15,000 BC and thus than in Europe. Northeastern Siberia was not covered by a continental-scale ice sheet. Instead, but restricted, icefield complexes covered mountain ranges within northeast Siberia, including the Kamchatka-Koryak Mountains; the Arctic Ocean between the huge ice sheets of America and Eurasia was not frozen throughout, but like today was only covered by shallow ice, subject to seasonal changes and riddled with icebergs calving from the surrounding ice sheets.
According to the sediment composition retrieved from deep-sea cores there must have been times of seasonally open waters. Outside the main ice sheets, widespread glaciation occurred on the highest mountains of the Alps−Himalaya mountain chain. In contrast to the earlier glacial stages, the Würm glaciation was composed of smaller ice caps and confined to valley glaciers, sending glacial lobes into the Alpine foreland; the [, the highest massifs of the Carpathian Mountains and the Balkanic peninsula mountains and to the east the Caucasus and the mountains of Turkey and Iran were capped by local ice fields or small ice sheets. In the Himalaya and the Tibetan Plateau, glaciers advanced particularly between 45,000 and 25,000 BC, but these datings are controversial; the formation of a contiguous ice sheet on the Tibetan Plateau is controversial. Other areas of the Northern Hemisphere did not bear extensive ice sheets, but local glaciers in high areas. Parts of Taiwan, for example, were glaciated between 42,250 and 8,680 BCE as well as the Japanese Alps
Cuicuilco is an important archaeological site located on the southern shore of Lake Texcoco in the southeastern Valley of Mexico, in what is today the borough of Tlalpan in Mexico City. The settlement goes back to 1400 BC. Cuicuilco flourished during the Mesoamerican Late Formative periods. Today, it is a significant archaeological site, occupied during the Early Formative until its destruction in the Late Formative. Based on its date of occupation, Cuicuilco may be the oldest city in the Valley of Mexico and was contemporary with, interacting with, the Olmec of the Gulf Coast of lowland Veracruz and Tabasco. Based on known facts, it was the first important civic-religious center of the Mexican Highlands, its population including all the social strata and cultural traits that would characterize the altépetl of classical Mesoamerica. Cuicuilco was destroyed and abandoned following the eruption of the volcano Xitle, causing migrations and changes to the population and culminating in the consolidation of Teotihuacan as the ruler of the Central Highlands during the Early Classic period.
At the site are eight of the many housing and religious buildings that once existed and the remains of a hydraulic system that supplied water to the city. One of the pyramids was built in a strategic position, representing early prehispanic attempts to link religious concepts with cosmic events through building construction; the etymology is unknown. According to Mexico's Instituto Nacional de Antropología e Historia, American archaeologist and anthropologist Zelia Nuttall believed that Cuicuilco means: “Place where songs and dances are made”. Cuicuilco was founded as a farming village, but provides evidence of early religious practices, including stone offerings and the use of ceramics as grave goods; the city grew around a large ceremonial center with pyramids and an associated urban area that included plazas and avenues bordering a series of small, shallow pools. These pools were fed by runoff from the nearby hills of Zacaltepetl; the population at the city's peak is estimated at 20,000 people.
The features of the site include terraces, various buildings and irrigation ditches and canals. The main known structure is a pyramidal basement built about 800–600 BCE. Although this site produced a new ceramic tradition, it is considered that the overall site area was developed over several generations of inhabitants. Archaeological evidence and structures, indicate that Cuicuilco developed during the first millennium BCE, during the Preclassic, as a small settlement, its inhabitants interacting with other sites in the Basin of Mexico as well as distant regions, e.g. Chupicuaro to the west and Monte Albán southeast. Estimated occupation periods for Cuicuilco may be considered tentative at best; the earliest occupation is estimated in 1200 BCE, included many farming villages of similar configuration and space distribution. During the period 1000–800 BCE, conical structures with an oval base were built. Specialists call these sites regional capitals, considering that they had higher hierarchy and functioned as integration centers becoming larger regional capitals.
If the great pyramid of Cuicuilco is an expression of this growth this level of development was reached between 800–600 BC, when it was built. If true, these proto-urban characteristics might have extended into the late Preclassic, with Cuicuilco weakening between 100 BCE and 1 CE, the time when Teotihuacan began to develop becoming an important urban center in the Classic period. In the mid-Preclassic, settlements emerged in the area, which evolved and grew, becoming cities, subsequently developing into a major civic-ceremonial urban centers in the late Preclassic; as an urban center, Cuicuilco became important, with an advanced and stratified society. Some experts theorize that the development of the site, from its foundation, was due to its strategic location near the pass of Toluca, near the shores of Lake Texcoco. Under this perspective, although the place produced a new ceramic tradition, is evident that the region was configured by successive generations. Towards the late Preclassic period, around 150 BCE, Cuicuilco became an urban regional center, with a population estimated at about 20,000 inhabitants, comparable with Teotihuacan at that time.
Cuicuilco's development was affected by the eruption of the Xitle volcano, which formed a layer of lava that or covered the city’s structures, whose extension is inferred to have reached nearly 400 hectares. The inhabitants had round heads affected by direct or oblique tubular cranial deformation, the first being more common. Dental mutilation was practised; the average life span was 51 years, affected by diseases like osteomyelitis. From their location, inhabitants had access to natural resources, as they were located 4 km from Lake Xochimilco, near the Sierra de las Cruces and Ajusco. Prehispanic groups managed to produce food; the economic base was centered on agriculture supplemented by hunting and gathering. The decline began in the early 1st century BCE, with the rise of Teotihuacán as a center of cultural and religious influence. By the year 400 CE, the Xitle volcano, located in the vicinity of Aj
A lake is an area filled with water, localized in a basin, surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, therefore are distinct from lagoons, are larger and deeper than ponds, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which are flowing. Most lakes streams. Natural lakes are found in mountainous areas, rift zones, areas with ongoing glaciation. Other lakes are found along the courses of mature rivers. In some parts of the world there are many lakes because of chaotic drainage patterns left over from the last Ice Age. All lakes are temporary over geologic time scales, as they will fill in with sediments or spill out of the basin containing them. Many lakes are artificial and are constructed for industrial or agricultural use, for hydro-electric power generation or domestic water supply, or for aesthetic, recreational purposes, or other activities.
The word lake comes from Middle English lake, from Old English lacu, from Proto-Germanic *lakō, from the Proto-Indo-European root *leǵ-. Cognates include Dutch laak, Middle Low German lāke as in: de:Wolfslake, de:Butterlake, German Lache, Icelandic lækur. Related are the English words leak and leach. There is considerable uncertainty about defining the difference between lakes and ponds, no current internationally accepted definition of either term across scientific disciplines or political boundaries exists. For example, limnologists have defined lakes as water bodies which are a larger version of a pond, which can have wave action on the shoreline or where wind-induced turbulence plays a major role in mixing the water column. None of these definitions excludes ponds and all are difficult to measure. For this reason, simple size-based definitions are used to separate ponds and lakes. Definitions for lake range in minimum sizes for a body of water from 2 hectares to 8 hectares. Charles Elton, one of the founders of ecology, regarded lakes as waterbodies of 40 hectares or more.
The term lake is used to describe a feature such as Lake Eyre, a dry basin most of the time but may become filled under seasonal conditions of heavy rainfall. In common usage, many lakes bear names ending with the word pond, a lesser number of names ending with lake are in quasi-technical fact, ponds. One textbook illustrates this point with the following: "In Newfoundland, for example every lake is called a pond, whereas in Wisconsin every pond is called a lake."One hydrology book proposes to define the term "lake" as a body of water with the following five characteristics: it or fills one or several basins connected by straits has the same water level in all parts it does not have regular intrusion of seawater a considerable portion of the sediment suspended in the water is captured by the basins the area measured at the mean water level exceeds an arbitrarily chosen threshold With the exception of the seawater intrusion criterion, the others have been accepted or elaborated upon by other hydrology publications.
The majority of lakes on Earth are freshwater, most lie in the Northern Hemisphere at higher latitudes. Canada, with a deranged drainage system has an estimated 31,752 lakes larger than 3 square kilometres and an unknown total number of lakes, but is estimated to be at least 2 million. Finland has larger, of which 56,000 are large. Most lakes have at least one natural outflow in the form of a river or stream, which maintain a lake's average level by allowing the drainage of excess water; some lakes do not have a natural outflow and lose water by evaporation or underground seepage or both. They are termed endorheic lakes. Many lakes are artificial and are constructed for hydro-electric power generation, aesthetic purposes, recreational purposes, industrial use, agricultural use or domestic water supply. Evidence of extraterrestrial lakes exists. Globally, lakes are outnumbered by ponds: of an estimated 304 million standing water bodies worldwide, 91% are 1 hectare or less in area. Small lakes are much more numerous than large lakes: in terms of area, one-third of the world's standing water is represented by lakes and ponds of 10 hectares or less.
However, large lakes account for much of the area of standing water with 122 large lakes of 1,000 square kilometres or more representing about 29% of the total global area of standing inland water. Hutchinson in 1957 published a monograph, regarded as a landmark discussion and classification of all major lake types, their origin, morphometric characteristics, distribution; as summarized and discussed by these researchers, Hutchinson presented in it a comprehensive analysis of the origin of lakes and proposed what is a accepted classification of lakes according to their origin. This
Mexico the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States. Covering 2,000,000 square kilometres, the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity, the capital city and its most populous city. Other metropolises in the state include Guadalajara, Puebla, Tijuana and León. Pre-Columbian Mexico dates to about 8000 BC and is identified as one of five cradles of civilization and was home to many advanced Mesoamerican civilizations such as the Olmec, Teotihuacan, Zapotec and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan, administered as the viceroyalty of New Spain.
Three centuries the territory became a nation state following its recognition in 1821 after the Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes; the Mexican–American War led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, the Porfiriato occurred in the 19th century; the Porfiriato was ended by the start of the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system as a federal, democratic republic. Mexico has the 11th largest by purchasing power parity; the Mexican economy is linked to those of its 1994 North American Free Trade Agreement partners the United States. In 1994, Mexico became the first Latin American member of the Organisation for Economic Co-operation and Development, it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts.
The country is considered both a regional power and a middle power, is identified as an emerging global power. Due to its rich culture and history, Mexico ranks first in the Americas and seventh in the world for number of UNESCO World Heritage Sites. Mexico is an ecologically megadiverse country, ranking fourth in the world for its biodiversity. Mexico receives a huge number of tourists every year: in 2018, it was the sixth most-visited country in the world, with 39 million international arrivals. Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus group of the UN, the Pacific Alliance trade bloc. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely the Valley of Mexico and surrounding territories, with its people being known as the Mexica, it is believed to be a toponym for the valley which became the primary ethnonym for the Aztec Triple Alliance as a result, although it could have been the other way around.
In the colonial era, back when Mexico was called New Spain this territory became the Intendency of Mexico and after New Spain achieved independence from the Spanish Empire it came to be known as the State of Mexico with the new country being named after its capital: the City of Mexico, which itself was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan. Traditionally, the name Tenochtitlan was thought to come from Nahuatl tetl and nōchtli and is thought to mean "Among the prickly pears rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggests the second vowel was short, so that the true etymology remains uncertain; the suffix -co is the Nahuatl locative, making the word a place name. Beyond that, the etymology is uncertain, it has been suggested that it is derived from Mextli or Mēxihtli, a secret name for the god of war and patron of the Mexica, Huitzilopochtli, in which case Mēxihco means "place where Huitzilopochtli lives".
Another hypothesis suggests that Mēxihco derives from a portmanteau of the Nahuatl words for "moon" and navel. This meaning might refer to Tenochtitlan's position in the middle of Lake Texcoco; the system of interconnected lakes, of which Texcoco formed the center, had the form of a rabbit, which the Mesoamericans pareidolically associated with the moon rabbit. Still another hypothesis suggests that the word is derived from Mēctli, the name of the goddess of maguey; the name of the city-state was transliterated to Spanish as México with the phonetic value of the letter x in Medieval Spanish, which represented the voiceless postalveolar fricative. This sound, as well as the voiced postalveolar fricative, represented by a j, evolved into a voiceless velar fricative during the 16th century; this led to the use of the variant Méjico in many publications in Spanish, most notably in Spain, whereas in Mexico and most other Spanish–speaking countries, México was the preferred spelling. In recent years, the Real Academia Española, which regulates the Spanish l