Taruga is an archeological site in Nigeria famous for the artifacts of the Nok culture that have been discovered there, some dating to 600 BC, for evidence of early iron working. The site is 60 km southeast of Abuja, in the Middle Belt. Taruga is just one of the sites in central Nigeria where artifacts from the Nok culture have been excavated. Since 1945, similar figurines and pottery have been found in many other locations in the area uncovered accidentally by modern tin miners, dating from before 500 BC to 200 AD; the region was moister and more wooded during this period than it is today, but was still north of the zone of dense forests. The people would have subsisted by farming and cattle raising; as the climate became drier, they would have drifted south, so the Nok people may have been the ancestors of people such as the Igala, Nupe and Ibo, whose artwork shows similarities to the earlier Nok artifacts. Early terracotta figurines from Taruga are decorated with bands of oblique comb stamping, parallel grooving, false relief chevron and incised hatched triangles.
These designs appear to have influenced subsequent Ife traditions. Styles are similar to findings from the Neolithic and Iron Age at Rim in Upper Volta, with decorations such as twisted and carved roulettes. Many of the heads or busts that have been found may once have been part of complete figures; the figurines represented tribal heroes and ancestors, would have been housed in shrines in permanent village compounds. Pottery is decorated with raised dots made by a carved roulette, which may cover most of the body of the pot; the dots are combined with grooved lines, may make a net-like pattern over the body of the pot. Both the figurines and the pottery were baked at low temperature, are therefore fragile. Bernard Fagg undertook a controlled evacuation of Taruga in the 1960s, finding both terracotta figurines and iron slag with radiocarbon dates from about the fourth and third centuries BC. Iron working at the site has now been dated to 600 BC, two hundred years before it began in Katsina-Ala, another Nok center.
This is the earliest known date for iron working in Sub-Saharan Africa. It has been speculated that iron smelting technology was introduced to the region from North Africa via Meroe, but it may well have developed indigenously, building on earlier copper-smelting technology in which iron ore was used as a flux; the beehive and cylindrical furnaces of West Africa are quite different in form from those of North Africa and Mesopotamia. The iron workers at Taruga seem to have developed the innovation of pre-heating the air entering the furnace so as to obtain higher temperatures. A short blade found at Taruga dating to around the fourth century BC was made from smaller pieces of metal forged together by a "piling" technique; the fragments obtained by smelting would have been wrapped in clay, heated to 1200 °C taken from the fire and forged to weld them into a single piece. This approach is sophisticated, since it prevented excessive oxidization during the long period of heating; the metal is extraordinarily free of impurities.
As of October 2007, the Federal Government was being asked to protect and rehabilitate the site in view of its tourist potential. However, the site was threatened by illegal miners looking to develop the mineral resources
Benin City is the capital of Edo State in southern Nigeria. It is situated 40 kilometres north of the Benin River and 320 kilometres by road east of Lagos. Benin City is the centre of Nigeria's rubber industry, oil production is a significant industry; the indigenous people of Benin City are Edo and they speak the Edo language and other Edoid languages. The people of Benin City are known as Bini; the people of the city have one of the richest dress cultures on the African continent and are known for their beads, body marks, bangles and raffia work. The original people and founders of the Ẹdo Empire and the Ẹdo people were ruled by the Ogiso dynasty who called their land Igodomigodo. Igodo, the first Ogiso, gained popularity as a good ruler, he was succeeded by Ere, his eldest son. In the 12th century, a great palace intrigue and battle for power erupted between the warrior crown prince Ekaladerhan, son of the last Ogiso and his young paternal uncle. In anger over an oracle, Prince Ekaladerhan left the royal court with his warriors.
When his old father the Ogiso died, the Ogiso dynasty was ended as the people and royal kingmakers preferred their king's son as natural next in line to rule. The exiled Ekaladerhan, not known, gained the title of Oni Ile-fe Izoduwa, corrected in the Yoruba language to Ọọni of Ile-Ifẹ Oduduwa, he sent his son Ọranmiyan to become king in his place. Prince Ọranmiyan took up residence in the palace built for him at Uzama by the elders, now a coronation shrine. Soon after he married a beautiful lady, Ẹrinmwide, daughter of Osa-nego, the ninth Enogie of Edọ, he and Erinwide had a son. After some years he called a meeting of the people and renounced his office, remarking that the country was a land of vexation, Ile-Ibinu, that only a child born and educated in the arts and mysteries of the land could reign over the people; the country was afterward known by this name. He caused his son born to him by Ẹrinmwide to be made King in his place, returned to Yoruba land Ile-Ife. After some years in Ife, he left for Ọyọ, where he left a son behind upon leaving, his son Ajaka became the first Alafin of Ọyọ of the present line, while Ọranmiyan himself was reigning as Ọọni of Ifẹ.
Therefore, Ọranmiyan of Ife, the father of Ẹwẹka I, the Ọba of Benin, was the father of Ajaka, the first Alafin of Ọyọ. Ọọni of Ifẹ. Ọba Ẹwẹka changed the name of the city of Ile-Binu, the capital of the Benin kingdom, to "Ubinu." This name would be reinterpreted by the Portuguese as "Benin" in their own language. Around 1470, Ẹwuare changed the name of the state to Ẹdo; this was about the time the people of Ọkpẹkpẹ migrated from Benin City. Alternatively, Yorubas believe Oduduwa was from the Middle East and migrated from that area to the present Ile Ife; because of his power and military might he was able to conqurer the enimies invading Ife city. That was why the people of Ile Ife made him the Oni of Ife city. In any case, it is agreed upon by both the Yoruba and Edos that Oduduwa sent his son Prince Oramiyan of Ife to rule Benin City and found the Oba dynasty in Benin City; the Portuguese visited Benin City around 1485. Benin grew rich during the 16th and 17th centuries due to trade within southern Nigeria, as well as through trade with Europeans in pepper and ivory.
In the early 16th century the Ọba sent an ambassador to Lisbon, the King of Portugal sent Christian missionaries to Benin. Some residents of Benin could still speak a pidgin Portuguese in the late 19th century. Many Portuguese loan words can still be found today in the languages of the area. A Portuguese captain described the city in 1691:“Great Benin, where the king resides, is larger than Lisbon; the houses are large that of the king, richly decorated and has fine columns. The city is industrious, it is so well governed that theft is unknown and the people live in such security that they have no doors to their houses.” This was at a time when murder were rife in London. On 17 February 1897, Benin City fell to the British. In the "Punitive Expedition", a 1,200-strong British force, under the command of Admiral Sir Harry Rawson and razed the city after all but two men from a previous British expeditionary force led by Acting Consul General Philips were killed. Alan Boisragon, one of the survivors of the Benin Massacre, includes references to the practice of human sacrifice in the city in a firsthand account written in 1898.
James D. Graham notes that although "there is little doubt that human sacrifices were an integral part of the Benin state religion from early days," firsthand accounts regarding such acts varied with some reporting them and others making no mention of them; the "Benin Bronzes", portrait figures and groups created in iron, carved ivory, in brass, were taken from the city by the British and are displayed in various museums around the world. Some of the bronzes were auctioned off to compensate for the expenses incurred during the invasion of the city. Most of these artifacts can be found today in other parts of the world. In recent years, various appeals have gone to the British government to return such artifacts; the most prominent of these artifacts was the famous Queen Idia mask used as a mascot during the Second Festival of Arts Culture held in Nigeria in 1977 now known as "Festac Mask". The capture of Benin
Durbi Takusheyi is a burial site and major archaeological landmark situated about 32 km east of Katsina in northern Nigeria. The burials of the early Katsina rulers span a 200 year period from the 13th / 14th century AD to the 15th / 16th century AD; the recovered sets of artifacts provide material historical clues as to the emergence of Hausa identity and city states. The grave goods comprise a local, indigenous component besides foreign elements which attest to networks that reached far into the Islamic Near East. Katsina represented a focal point for trans-Saharan trade during the late middle ages, a crucial phase in local history during which the Hausa city states emerged. Microliths found in 1965 on the mounds by R. C. Soper suggest that the vicinity of Katsina was continuously settled since the stone age; the early history of one of the Hausa kingdoms, namely the kingdom of Katsina, was centered on several sites, of which Durbi Takusheyi was the most notable. It acquired its privileged status at some time before the 15th century due to the presence of shrines for ancestor idols located at baobabs near the tumuli.
Local tradition holds that the clan, identified with the Durbawa venerated a solar deity and that their chief priest held the title of "Durbi", still a senior title in the Katsina Emirate. Usman states that the agrarian, proto-urban villages of the region were presided over by a town head, the supposed representative of a senior lineage; the authority of the town heads in the Katsina area was based on their control of, identification with, the ancestor cults centered on the Durbi tombs. Durbi Takusheyi's ancestor cult and degree of political hegemony withered in favour of a nature worship cult centered on the shrine of Yuna, at the tamarind tree of Bawada, near Tilla; the Durbi tombs were overlooked by westerners until Palmer initiated the first excavations in 1907. On 23 April 1959 the Nigerian Antiquities Department declared the site a national heritage monument. In 1959 it was taken to include three large and two small tumuli, in addition to the old baobab tree known as Kuka Katsi, the site of the former tree known as Kuka Kumayo.
There are however eight or nine tumuli, each with one central, individual interment, spanning some 200 years. They are situated in a flat to undulating landscape, characterized by granite hills and sandy terraces. Excavated objects include pottery, grinding stones, iron spear heads, faunal remains, brass bars, cornelian beads and golden earrings; the burial goods were fabricated from both organic materials. A bowl of Near Eastern origin in tumulus 7, dated to the late 15th to early 16th century, attests to increased international and Islamic influence at this time. Among the decorative body ornaments were a beaded belt in tumulus 7, a cap or headpiece covered in cowry shells and a fur-lined spiked leg bracelet or guard in tumulus 4, a belt decorated in cowry shells in tumulus 5; the non-ferrous metal objects were made of copper-based alloys or silver. They range from bracelets and/or anklets of various forms and manufacturing techniques and leg guards, to bowls, buckets and finery such as beads and forks.
Their manufacturing and metal types suggest imported finished and unfinished imported objects as well as locally manufactured and/or locally modified objects. Chemical and lead isotopic analyses revealed metals from Africa to Iran; the mounds were excavated in 1907 by Herbert Richmond Palmer in cooperation with the Emir of Katsina, Muhammadu Dikko. The largest mound and two others were excavated when no clear information about their history could be obtained, they found ceramic and metallic goods, but all the items of this first excavation appear to be lost with only minimal information preserved. The second excavation was headed by Dierk Lange of Bayreuth and funded by the German Research Foundation. Three additional mounds were discovered, numbered 4, 5 and 7, which were excavated during 1991 and 1992; each mound was found to contain one interment at its centre. The associated burial goods were made from inorganic materials such as metal, glass and cowries, besides organic materials such as cloth and hides.
Though some artifacts were of local origin, others hailed from distant Islamic locations. Radiocarbon tests dated one group of artifacts to the early 14th century AD, while typology and art history placed another set of artifacts in the late 15th to early 16th century; the recovered items were first stored in Katsina transferred to the Gidan Makama Museum in Kano, deposited at the Jos Museum for further analyses. In 2007 it was shipped to the Romano-Germanic Central Museum in Mainz for general conservation. In 2005, German archaeologists led by Prof. Peter Breunig started excavations of several sites related to the Nok culture, they gained the approval of the Nigerian museums commission to restore and analyze the Durbi Takusheyi artifacts. In 2007, the scholars are said to have exported "tons of materials" excavated from Durbi Takusheyi for restoration and conservation at the Romano-Germanic Central Museum in Mainz. In 2011 the museum opened the first exhibition of the materials, along with Nok culture artifacts, all items were expected to be returned to Nigeria in 2012.
Arrangements for the return of artifacts exported since the 1990s were concluded in 2014. The collection arrived in Abuja that year, from where it was taken to the National Museum in Katsina, it was first displayed in Katsina during 2015's International Museum Day celebration. Various myths
Great Wall of China
The Great Wall of China is a series of fortifications made of stone, tamped earth and other materials built along an east-to-west line across the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe with an eye to expansion. Several walls were being built from as early as the 7th century BC. Little of that wall remains. On, many successive dynasties have repaired and newly built multiple stretches of border walls; the most well-known of the walls were built during the Ming dynasty. Apart from defense, other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration. Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, the fact that the path of the Great Wall served as a transportation corridor.
The frontier walls built by different dynasties have multiple courses. Collectively, they stretch from Dandong in the east to Lop Lake in the west, from present-day Sino-Russian border in the north to Qinghai in the south. A comprehensive archaeological survey, using advanced technologies, has concluded that the walls built by the Ming dynasty measure 8,850 km; this is made up of 6,259 km sections of actual wall, 359 km of trenches and 2,232 km of natural defensive barriers such as hills and rivers. Another archaeological survey found that the entire wall with all of its branches measures out to be 21,196 km. Today, the Great Wall is recognized as one of the most impressive architectural feats in history; the collection of fortifications known as the Great Wall of China has had a number of different names in both Chinese and English. In Chinese histories, the term "Long Rampart" appears in Sima Qian's Records of the Grand Historian, where it referred both to the separate great walls built between and north of the Warring States and to the more unified construction of the First Emperor.
The Chinese character 城, meaning city or fortress, is a phono-semantic compound of the "earth" radical 土 and phonetic 成, whose Old Chinese pronunciation has been reconstructed as *deŋ. It referred to the rampart which surrounded traditional Chinese cities and was used by extension for these walls around their respective states; the longer Chinese name "Ten-Thousand Mile Long Wall" came from Sima Qian's description of it in the Records, though he did not name the walls as such. The AD 493 Book of Song quotes the frontier general Tan Daoji referring to "the long wall of 10,000 miles", closer to the modern name, but the name features in pre-modern times otherwise; the traditional Chinese mile was an irregular distance, intended to show the length of a standard village and varied with terrain but was standardized at distances around a third of an English mile. Since China's metrication in 1930, it has been equivalent to 500 metres or 1,600 feet, which would make the wall's name describe a distance of 5,000 km.
However, this use of "ten-thousand" is figurative in a similar manner to the Greek and English myriad and means "innumerable" or "immeasurable". Because of the wall's association with the First Emperor's supposed tyranny, the Chinese dynasties after Qin avoided referring to their own additions to the wall by the name "Long Wall". Instead, various terms were used in medieval records, including "frontier", "rampart", "barrier", "the outer fortresses", "the border wall". Poetic and informal names for the wall included "the Purple Frontier" and "the Earth Dragon". Only during the Qing period did "Long Wall" become the catch-all term to refer to the many border walls regardless of their location or dynastic origin, equivalent to the English "Great Wall"; the current English name evolved from accounts of "the Chinese wall" from early modern European travelers. By the 19th century, "The Great Wall of China" had become standard in English and French, although other European languages such as German continue to refer to it as "the Chinese wall."
The Chinese were familiar with the techniques of wall-building by the time of the Spring and Autumn period between the 8th and 5th centuries BC. During this time and the subsequent Warring States period, the states of Qin, Zhao, Qi, Zhongshan all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made by stamping earth and gravel between board frames. King Zheng of Qin conquered the last of his opponents and unified China as the First Emperor of the Qin dynasty in 221 BC. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the sections of the walls that divided his empire among the former states. To position the empire against the Xiongnu people from the north, however, he ordered the building of new walls to connect the remaining fortifications along the empire's northern frontier. "Build and move on" was a central guiding principle in
In mathematics, a fractal is a subset of a Euclidean space for which the Hausdorff dimension exceeds the topological dimension. Fractals tend to appear nearly the same at different levels, as is illustrated here in the successively small magnifications of the Mandelbrot set. Fractals exhibit similar patterns at small scales called self similarity known as expanding symmetry or unfolding symmetry. One way that fractals are different from finite geometric figures is the way. Doubling the edge lengths of a polygon multiplies its area by four, two raised to the power of two. If the radius of a sphere is doubled, its volume scales by eight, two to the power of three. However, if a fractal's one-dimensional lengths are all doubled, the spatial content of the fractal scales by a power, not an integer; this power is called the fractal dimension of the fractal, it exceeds the fractal's topological dimension. Analytically, fractals are nowhere differentiable. An infinite fractal curve can be conceived of as winding through space differently from an ordinary line – although it is still 1-dimensional, its fractal dimension indicates that it resembles a surface.
Starting in the 17th century with notions of recursion, fractals have moved through rigorous mathematical treatment of the concept to the study of continuous but not differentiable functions in the 19th century by the seminal work of Bernard Bolzano, Bernhard Riemann, Karl Weierstrass, on to the coining of the word fractal in the 20th century with a subsequent burgeoning of interest in fractals and computer-based modelling in the 20th century. The term "fractal" was first used by mathematician Benoit Mandelbrot in 1975. Mandelbrot based it on the Latin frāctus, meaning "broken" or "fractured", used it to extend the concept of theoretical fractional dimensions to geometric patterns in nature. There is some disagreement among mathematicians about how the concept of a fractal should be formally defined. Mandelbrot himself summarized it as "beautiful, damn hard useful. That's fractals." More formally, in 1982 Mandelbrot stated that "A fractal is by definition a set for which the Hausdorff–Besicovitch dimension exceeds the topological dimension."
Seeing this as too restrictive, he simplified and expanded the definition to: "A fractal is a shape made of parts similar to the whole in some way." Still Mandelbrot settled on this use of the language: "...to use fractal without a pedantic definition, to use fractal dimension as a generic term applicable to all the variants". The consensus is that theoretical fractals are infinitely self-similar and detailed mathematical constructs having fractal dimensions, of which many examples have been formulated and studied in great depth. Fractals are not limited to geometric patterns, but can describe processes in time. Fractal patterns with various degrees of self-similarity have been rendered or studied in images and sounds and found in nature, art and law. Fractals are of particular relevance in the field of chaos theory, since the graphs of most chaotic processes are fractals; the word "fractal" has different connotations for laymen as opposed to mathematicians, where the layman is more to be familiar with fractal art than the mathematical concept.
The mathematical concept is difficult to define formally for mathematicians, but key features can be understood with little mathematical background. The feature of "self-similarity", for instance, is understood by analogy to zooming in with a lens or other device that zooms in on digital images to uncover finer invisible, new structure. If this is done on fractals, however, no new detail appears. Self-similarity itself is not counter-intuitive; the difference for fractals is. This idea of being detailed relates to another feature that can be understood without mathematical background: Having a fractal dimension greater than its topological dimension, for instance, refers to how a fractal scales compared to how geometric shapes are perceived. A regular line, for instance, is conventionally understood to be one-dimensional. A solid square is understood to be two-dimensional. We see that for ordinary self-similar objects, being n-dimensional means that when it is rep-tiled into pieces each scaled down by a scale-factor of 1/r, there are a total of rn pieces.
Now, consider the Koch curve. It can be rep-tiled into four sub-copies, each scaled down by a scale-factor of 1/3. So by analogy, we can consider the "dimension" of the Koch curve as being the unique real number D that satisfies 3D = 4, which by no means is an integer! This number is; the fact th
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza pyramid complex bordering present-day El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, the only one to remain intact. Based on a mark in an interior chamber naming the work gang and a reference to the fourth dynasty Egyptian Pharaoh Khufu, some Egyptologists believe that the pyramid was thus built as a tomb over a 10- to 20-year period concluding around 2560 BC. At 146.5 metres, the Great Pyramid was the tallest man-made structure in the world for more than 3,800 years. The Great Pyramid was covered by limestone casing stones that formed a smooth outer surface; some of the casing stones that once covered the structure can still be seen around the base. There have been varying scientific and alternative theories about the Great Pyramid's construction techniques. Most accepted construction hypotheses are based on the idea that it was built by moving huge stones from a quarry and dragging and lifting them into place.
There are three known chambers inside the Great Pyramid. The lowest chamber was unfinished; the so-called Queen's Chamber and King's Chamber are higher up within the pyramid structure. The main part of the Giza complex is a set of buildings that included two mortuary temples in honour of Khufu, three smaller pyramids for Khufu's wives, an smaller "satellite" pyramid, a raised causeway connecting the two temples, small mastaba tombs surrounding the pyramid for nobles. Egyptologists believe the pyramid was built as a tomb for the Fourth Dynasty Egyptian pharaoh Khufu and was constructed over a 20-year period. Khufu's vizier, Hemiunu is believed by some to be the architect of the Great Pyramid, it is thought that, at construction, the Great Pyramid was 280 Egyptian Royal cubits tall, but with erosion and absence of its pyramidion, its present height is 138.8 metres. Each base side was 440 cubits, 230.4 metres long. The mass of the pyramid is estimated at 5.9 million tonnes. The volume, including an internal hillock, is 2,500,000 cubic metres.
Based on these estimates, building the pyramid in 20 years would involve installing 800 tonnes of stone every day. Additionally, since it consists of an estimated 2.3 million blocks, completing the building in 20 years would involve moving an average of more than 12 of the blocks into place each hour and night. The first precision measurements of the pyramid were made by Egyptologist Sir Flinders Petrie in 1880–82 and published as The Pyramids and Temples of Gizeh. All reports are based on his measurements. Many of the casing-stones and inner chamber blocks of the Great Pyramid fit together with high precision. Based on measurements taken on the north-eastern casing stones, the mean opening of the joints is only 0.5 millimetres wide. The pyramid remained the tallest man-made structure in the world for over 3,800 years, unsurpassed until the 160-metre-tall spire of Lincoln Cathedral was completed c. 1300. The accuracy of the pyramid's workmanship is such that the four sides of the base have an average error of only 58 millimetres in length.
The base is flat to within ± 15 mm. The sides of the square base are aligned to the four cardinal compass points based on true north, not magnetic north, the finished base was squared to a mean corner error of only 12 seconds of arc; the completed design dimensions, as suggested by Petrie's survey and subsequent studies, are estimated to have been 280 Egyptian Royal cubits high by 440 cubits long at each of the four sides of its base. The ratio of the perimeter to height of 1760/280 Egyptian Royal cubits equates to 2π to an accuracy of better than 0.05 percent. Some Egyptologists consider this to have been the result of deliberate design proportion. Verner wrote, "We can conclude that although the ancient Egyptians could not define the value of π, in practice they used it". Petrie concluded: "but these relations of areas and of circular ratio are so systematic that we should grant that they were in the builder's design". Others have argued that the ancient Egyptians had no concept of pi and would not have thought to encode it in their monuments.
They believe that the observed pyramid slope may be based on a simple seked slope choice alone, with no regard to the overall size and proportions of the finished building. In 2013, rolls of papyrus called the Diary of Merer were discovered written by some of those who delivered limestone and other construction materials from Tora to Giza; the Great Pyramid consists of an estimated 2.3 million blocks which most believe to have been transported from nearby quarries. The Tura limestone used; the largest granite stones in the pyramid, found in the "King's" chamber, weigh 25 to 80 tonnes and were transported from Aswan, more than 800 km away. Traditionally, ancient Egyptians cut stone blocks by hammering into them wooden wedges, which were soaked with water; as the water was absorbed, the wedges expanded. Once they were cut, they were carried by boat either down the Nile River to the pyramid, it is estimated that 5.5 million tonnes of limestone, 8,000 tonnes of granite, 500,000 tonnes of mortar were used in the construction of the Great Py
In archaeology, earthworks are artificial changes in land level made from piles of artificially placed or sculpted rocks and soil. Earthworks can themselves be archaeological features. Earthworks of interest to archaeologists include hill forts, mounds, platform mounds, effigy mounds, long barrows, tumuli and furrow, round barrows, other tombs. Hill forts, a type of fort made out of earth and other natural materials including sand and water, were built as early as the late Stone Age and were built more during the Bronze Age and Iron Age as a means of protection. See Oppidum. Henge earthworks are those that consist of a flat area of earth in a circular shape that are encircled by a ditch, or several circular ditches, with a bank on the outside of the ditch built with the earth from inside the ditch, they are believed to have been used as monuments for spiritual ritual ceremonies. A mound is a substantial manmade pile of earth or rocks, created to mark burial sites Platform mounds are pyramid or rectangular-shaped mounds that are used to hold a building or temple on top.
An effigy mound is a pile of earth very large in scale, shaped into the image of a person or animal for symbolic or spiritual reasons An enclosure is a space, surrounded by an earthwork. Long barrows are oblong-shaped mounds. A tumulus or barrow is a mound of earth created over a tomb. A cross dyke or cross-ridge dyke is a bank and ditch, or sometimes a ditch between two banks, that crosses a ridge or spur of high ground. Found in Europe and belonging to the Bronze Age or Iron Age. Marked on Ordnance Survey maps in the UK. Ridge and furrows are sets of parallel depressions and ridges in the ground formed through historic farming techniques. Mottes are mound structures made of stone that once held castles, they are an important part of the motte-and-bailey castle, a castle design during early Norman times in which the castle is built on the motte, surrounded by a ditch and a bailey, an enclosure with a stone wall. A round barrow is a mound, in a rounded shape, used during Neolithic times as a burial mound.
Geoglyph, a large design or motif Earthworks can vary in height from a few centimetres to the size of Silbury Hill at 40 metres. They can date from the Neolithic to the present; the structures can stretch for many tens of kilometres. In area, they can cover many hectares. Shallow earthworks are more visible as cropmarks or in aerial photographs if taken when the sun is low in the sky and shadows are more pronounced. Earthworks may be more visible after a frost or a light dusting of snow. Earthworks plotted using Light Detection and Ranging; this technique is useful for mapping small variations in land height that would be difficult to detect by eye. It can be used for features hidden by other vegetation. LIDAR results can be input into a geographic information system to produce three-dimensional representations of the earthworks. An accurate survey of the earthworks can enable them to be interpreted without the need for excavation. For example, earthworks from deserted medieval villages can be used to determine the location and layout of lost settlements.
These earthworks can point to the purpose of such a settlement, as well the context in which it existed. Earthworks in North America include mounds built by Native Americans known as the Mound Builders. Ancient people who lived in the American Midwest built effigy mounds, which are mounds shaped like animals or people; the most famous of these effigy mounds is Serpent Mound. Located in the Ohio, this 411-meterlong earthen work is thought to memorialize alignments of the planets and stars that were of special significance to the Native Americans that constructed it. Cone-shaped or conical mounds are numerous, with thousands of them scattered across the American Midwest, some over 80 feet tall; these conical mounds appear to be marking the graves of one person or dozens of people. An example of a conical mound is the Miamisburg Mound in central Ohio, estimated to have been built by people of the Adena culture in the time range of 800 B. C. to 100 AD. The American Plains hold temple mounds, or platform mounds, which are giant pyramid-shaped mounds with flat tops that once held temples made of wood.
Examples of temple mounds include Monks Mound located at the Cahokia site in Collinsville and Mound H at the Crystal River site in Citrus County, Florida. The earthworks at Poverty Point occupy one of the largest-area sites in North America, as they cover some 920 acres of land in Louisiana. Military earthworks can result in subsequent archaeological earthworks. Examples include Roman marching forts. During the American Civil War, earthwork fortifications were built throughout the country, by both Confederate and Union sides; the largest earthwork fort built during the war was Fortress Rosecrans, which encompassed 255 acres. In northeastern Somalia, near the city of Bosaso at the end of the Baladi valley, lies an earthwork 2 km to 3 km long. Local tradition recounts, it is the largest such structure in the wider Horn region. Bigo is an extensive earthworks site located in the interlacustrine region of southwestern Uganda, Africa. Situated on the south shore of the Katonga river, the Big