{"it":{"id":"NAM-013","kind":"site","sub":"North America","name":"Serpent Mound","place":"United States","lat":39.026,"lon":-83.431,"date":"In 2014, radiocarbon dating determined the mound was built in 300 BCE by the Adena…","mat":"clay;quartz","facts":[{"a":"14C date","v":"c.300 BCE (2014); repaired c.1100 CE","u":"text","r":47}],"nfacts":14,"tags":["North America"],"sum":"Serpent Mound, in Ohio, is a giant earthen snake about 411 m long, the largest serpent effigy in the world. Radiocarbon dating in 2014 refined its date.","why":"One of the world's great effigy mounds, whose builders are still in dispute.","src":[387],"nsrc":2,"yt":"Did the builders know?","rel":["NAM-010"],"hook":"Radiocarbon in 1991 made Serpent Mound about 900 years old. A 2014 team said 300 B.C."},"S":{"47":["Wikipedia Serpent Mound","https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562"],"387":["Wikipedia: Serpent Mound","https://en.wikipedia.org/wiki/Serpent_Mound"]},"rec":{"id":"NAM-013","alias":[],"ms":[{"f":"The Great Serpent Mound is a 1 348-feet-long","a":"height","v":"411","u":"m","o":"The Great Serpent Mound is a 1,348-feet-long (411m), four-feet-high precontact effigy mound located in Peebles, Ohio, United States.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2238"},{"f":"up of three parts Serpent Mound extends over","a":"length","v":"1348","u":"ft","o":"Made up of three parts, Serpent Mound extends over 1348 ft in length, varying from 9 in to more than 3 ft in height.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2239"},{"f":"length varying from 9 in to more than","a":"height","v":"3","u":"ft","o":"Made up of three parts, Serpent Mound extends over 1348 ft in length, varying from 9 in to more than 3 ft in height.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2240"},{"f":"stands with a width varying between 22 and","a":"dimension (unspecified)","v":"24","u":"ft","o":"The mound stands with a width varying between 22 and 24 ft based on the section.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2241"},{"f":"engulfs an east-facing hollow oval feature and is","a":"length","v":"120","u":"ft","o":"Squier and Davis interpreted the structure as an open-mouth head of a [serpent] that nearly engulfs an east-facing hollow oval feature and is 120 ft long.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2242"},{"f":"of the effigy features a triangular mound approximately","a":"base length/width","v":"31.6","u":"ft","o":"The western side of the effigy features a triangular mound approximately 31.6 ft at its base and long axis.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2243"},{"f":"The crater is around 8 7 miles","a":"diameter","v":"14","u":"km","o":"The crater is around 8.7 miles (14 km) in diameter and was formed 252–330 million years ago.","unc":"","by":"per cited source (see citation)","yr":"","m":"documentary: verbatim sentence auto-extracted from Wikipedia revision","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary); unit/attribute classified by keyword - check context in value_original","t":"MEASUREMENT","n":"","id":"M2244"},{"f":"site chronology","a":"dating (as stated)","v":"REF8 In 2014, radiocarbon dating determined the mound was built in 300 B","u":"","o":"REF8 In 2014, radiocarbon dating determined the mound was built in 300 BCE by the Adena peoples.","unc":"","by":"per cited source","yr":"","m":"documentary: auto-extracted sentence","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary)","t":"INTERPRETATION","n":"","id":"M2245"},{"f":"site chronology","a":"dating (as stated)","v":"1070 CE, with the third piece dating to 2920+/-65 years BP (before the present)","u":"","o":"When the team conducted carbon dating studies on the charcoal pieces, two yielded a date of ca. 1070 CE, with the third piece dating to 2920+/-65 years BP (before the present).","unc":"","by":"per cited source","yr":"","m":"documentary: auto-extracted sentence","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary)","t":"INTERPRETATION","n":"","id":"M2246"},{"f":"site chronology","a":"dating (as stated)","v":"2900 BP, was recovered from a core sample below the cultural mod","u":"","o":"The third date, ca. 2900 BP, was recovered from a core sample below the cultural modification level.","unc":"","by":"per cited source","yr":"","m":"documentary: auto-extracted sentence","c":"no inline ref in article","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"auto-extracted, Wikipedia rev 1378361562 (tertiary)","t":"INTERPRETATION","n":"","id":"M2247"},{"f":"effigy","a":"length","v":"411","u":"m","o":"","unc":"","by":"Wikipedia Serpent Mound","yr":"2026","m":"as stated","c":"Wikipedia Serpent Mound","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"","t":"MEASUREMENT","n":"","id":"M3637"},{"f":"effigy","a":"width","v":"6.7-7.3","u":"m","o":"","unc":"","by":"Wikipedia Serpent Mound","yr":"2026","m":"as stated","c":"Wikipedia Serpent Mound","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"","t":"MEASUREMENT","n":"","id":"M3638"},{"f":"construction","a":"14C date","v":"c.300 BCE (2014); repaired c.1100 CE","u":"text","o":"","unc":"","by":"Wikipedia Serpent Mound","yr":"2026","m":"derived","c":"Wikipedia Serpent Mound","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"","t":"LAB_RESULT","n":"Adena","id":"M3639"},{"f":"crater","a":"diameter","v":"~14 km","u":"km","o":"","unc":"","by":"Wikipedia Serpent Mound","yr":"2026","m":"as stated","c":"Wikipedia Serpent Mound","pg":"","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562","b":"S","bb":"","t":"MEASUREMENT","n":"252-330 Myr","id":"M3640"}],"lab":[{"k":"Materials","mat":"site material (as stated in article)","m":"documentary mention (Wikipedia, auto-extracted)","v":"In 2012, a group that identified themselves as \"light warriors\" vandalized the Serpent Mound by running and jumping on its surface, as well as burying quartz in and around the mound to \"reactivate\" it.","by":"no inline ref in article","b":"S","url":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562"}],"eng":[],"ori":[],"gaps":[],"dat":[],"aa":[],"ac":[],"me":[],"ci":[],"cq":[],"sd":[],"sub":[],"site":{"age":"In 2014, radiocarbon dating determined the mound was built in 300 BCE by the Adena peoples.","dm":"[see dating_excerpt; method not extracted]","lab":"NO: inference only (style/context/king list/textual)","weak":"no direct lab result on the structure in our records; date from stylistic, contextual or textual inference","unesco":"","dens":"CENSUS"},"co":{"lat":"39.02638889","lon":"-83.43083333","src":"Wikidata P625 only + curated wave0 value agrees","agree":"agree","b":"V","note":"two independent sources agree; max delta 0.0007 deg (~0.08 km)","osm":"https://www.openstreetmap.org/relation/18046217"},"src":[{"id":"S0384","t":"no inline ref in article","u":"https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562"},{"id":"S0605","t":"Wikipedia: Serpent Mound","u":"https://en.wikipedia.org/wiki/Serpent_Mound"},{"id":"VNAM-013-3","t":"Ohio History Connection: Serpent Mound","u":"https://www.ohiohistory.org/visit/browse-historical-sites/serpent-mound/"},{"id":"VNAM-013-4","t":"Ohio Archaeological Council: Serpent Mound document (PDF)","u":"https://ohioarchaeology.org/file_download/7b68bea3-ebae-486a-9cd8-7d0cec331570"},{"id":null,"t":"Ohio History Connection, “Serpent Mound” (site page, History).","u":"https://web.archive.org/web/2025/https://www.ohiohistory.org/visit/browse-historical-sites/serpent-mound/"},{"id":null,"t":"Bill Pickard, “The Snake’s Tale: How Old Is Serpent Mound?”, Ohio History Connection, 3 May 2011.","u":"https://web.archive.org/web/2025/https://www.ohiohistory.org/the-snakes-tale-how-old-is-serpent-mound/"},{"id":null,"t":"Edward W. Herrmann et al., “A new multistage construction chronology for the Great Serpent Mound, USA,” Journal of Archaeological Science 50 (2014): 117–125, abstract (SUNY Research Connect).","u":"https://researchconnect.suny.edu/en/publications/a-new-multistage-construction-chronology-for-the-great-serpent-mo/"},{"id":null,"t":"Ohio Division of Geological Survey, Ohio Geology newsletter, Winter 1994 (PDF).","u":"https://dam.assets.ohio.gov/image/upload/ohiodnr.gov/documents/geology/OGN_1994_n3Winter.pdf"}],"sum":"Deep under a wooded bluff in southern Ohio, the bedrock is shattered. The rock is broken across a zone miles wide, the mark of a violent event in the deep past. Geologists call it the Serpent Mound cryptoexplosion structure, and they still argue about its cause and its age. On its western flank, along the top of that broken ground, someone built a snake out of earth more than a quarter of a mile long.\n\nSerpent Mound lies in Adams County, on a narrow bluff above the point where East Creek meets Ohio Brush Creek. It is an earthen embankment in the form of a snake with a curled tail, about 411 metres, or 1,348 feet, from end to end, and it is the largest surviving, well-documented effigy mound in the world, an effigy mound being one built in the shape of an animal. The body is about 6 to 7.6 metres wide at its base and stands roughly 1.2 to 1.5 metres high, though other measurements run from nine inches to more than three feet. It follows a crescent-shaped course along the bluff. At its north-west end the open jaws meet an oval embankment about 37 by 18 metres, which Ephraim Squier and Edwin Davis read in 1848 as an egg the serpent was swallowing; others call it the eye. Three burial mounds lie nearby. The site is a National Historic Landmark, and in 2008 it was one of nine Ohio earthworks placed on the United States' Tentative List for World Heritage.\n\nThe ground beneath it is the first puzzle. The Ohio geological survey describes a zone of shattered rock left by a violent event dated somewhere between about 345 million and 125,000 years ago. Some geologists think an asteroid caused it; others favour an eruption of gases from deep in the Earth. The size is reported differently, about four miles across in the survey's 1994 account and around 14 kilometres, or 8.7 miles, in others. Erosion has since erased any crater from the landscape. Some have suggested they chose the spot on purpose; the survey notes only that the idea has been raised.\n\nThe second puzzle is the sky. In 1987 Clark and Marjorie Hardman published their finding that the line from the oval to the head points to the summer solstice sunset, and that the coiled tail aligns with the winter solstice sunrise. The three curves of the body may point to other sunrises at the solstices and equinox, or to key moonrises in the long lunar cycle. If even part of this holds, the snake is not only an image. It is a calendar laid along a ridge.\n\nThe third puzzle is who built it. Squier and Davis first published the mound in 1848 in Ancient Monuments of the Mississippi Valley, the Smithsonian's first publication. A tornado tore through in 1859, and by the 1880s the land was ploughed and grazed. The Harvard archaeologist Frederic Ward Putnam first visited in 1883 and found the snake much lower than Squier and Davis had recorded. He raised money for Harvard's Peabody Museum to buy the land in the mid-1880s, dug trenches across the effigy, and then restored it to its original dimensions. He found no artefacts inside the snake that could tie it to any culture. He did note that it sat on a prepared surface of ash and small cobbles, and that the dark topsoil had been stripped away before building began. In a nearby conical mound he found a principal burial of the Adena culture.\n\nThat neighbour shaped a century of thinking. Two conical mounds beside the snake belong to the Adena culture, dated to about 800 BC to AD 100; a small elliptical one belongs to the Fort Ancient culture, about AD 1000 to 1650. Because of the Adena mounds, archaeologists credited the snake to the Adena. Then, in 1991, Robert Fletcher, Terry Cameron and a small crew reopened what they took to be one of Putnam's old trenches and dated charcoal from it. Two samples came out around AD 1070, though a third gave 2920 years before the present, give or take 65. The crew read the dates as placing the effigy between AD 995 and 1265, and the Fort Ancient people became the likely builders. Some archaeologists have gone further and wondered whether Halley's comet, whose brightest recorded display came in 1066, inspired the giant serpent. That idea depends entirely on the later date.\n\nIn 2014 a team led by Edward Herrmann used geophysics and took 18 cores of solid earth, obtaining seven radiocarbon ages from the base of the mound. A statistical model of those dates suggested the snake was first built about 2,300 years ago, around 300 BC, by the Adena, and repaired roughly 1,400 years later by Fort Ancient people. Their magnetometer survey also showed what may be an abandoned coil near the head, visible only to the instrument. On this view, the 1991 charcoal records later repair, not original building.\n\nBradley Lepper of the Ohio History Connection disagrees. He points out that the 2014 dates came from soil humates in bulk sediment, not clean charcoal, and cites a Danish study in which charcoal from soil cores in mounds gave ages hundreds to thousands of years too old, including a mound dated by tree rings to AD 970 or 971 whose core charcoal came out 550 to 700 years older. If the Adena had once burned the bluff, their old charcoal could still have filled the soil when Fort Ancient builders came a thousand years later. In his reading the 2014 data show only that the mound could have been built any time after 300 BC: an earliest possible age, not a building date. The Ohio History Connection, which manages the site, says plainly that more work is needed.\n\nThe mound still draws more than archaeologists. In 2012 a group calling themselves \"light warriors\" ran and jumped on it and buried quartz in and around it to \"reactivate\" it, a reminder of how easily a real mystery attracts unreal answers.\n\nThe real questions are hard enough. Why did Putnam find nothing inside the snake? What does the faint extra coil near the head mean? And how did a people without writing lay out a serpent a quarter-mile long so that its head and tail point to the turning points of the sun, on the flank of a zone of shattered bedrock? If the same snake can be dated twice, a thousand years apart, and the experts still cannot agree, which culture built the Serpent, and how would we ever know for sure?","qs":["Which culture built the Serpent, and how would we know for sure?","Why did Putnam find nothing inside?","What would a better date need?"],"gal":[{"src":"https://upload.wikimedia.org/wikipedia/commons/3/31/Serpent_Mound%2C_Peebles%2C_Ohio_04.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail_unscaled","page":"https://commons.wikimedia.org/wiki/File:Serpent_Mound,_Peebles,_Ohio_04.jpg","title":"Serpent Mound, Peebles, Ohio 04.jpg","lic":"CC BY-SA 4.0","licurl":"https://creativecommons.org/licenses/by-sa/4.0","by":"Stephanie A. Terry","cap":"Serpent Mound atop a plateau above the Serpent Mound crater, an ancient meteor crater along Ohio Brush Creek."},{"src":"https://upload.wikimedia.org/wikipedia/commons/d/d9/Fort_Ancient_Tools_and_other_artifacts_HRoe_2011.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail_unscaled","page":"https://commons.wikimedia.org/wiki/File:Fort_Ancient_Tools_and_other_artifacts_HRoe_2011.jpg","title":"Fort Ancient Tools and other artifacts HRoe 2011.jpg","lic":"CC BY-SA 3.0","licurl":"https://creativecommons.org/licenses/by-sa/3.0","by":"Herb Roe, www.chromesun.com","cap":"A selection of tools and other artifacts from the Fort Ancient culture on display in a museum in Maysville, Ky. Includes bone awls, stone discoidals used for th"},{"src":"https://upload.wikimedia.org/wikipedia/commons/6/64/Mound_Builder_City.jpeg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail_unscaled","page":"https://commons.wikimedia.org/wiki/File:Mound_Builder_City.jpeg","title":"Mound Builder City.jpeg","lic":"Public domain","licurl":"","by":"user:RHorning","cap":"An artists conception of the Emerald Site, (22 AD 504), a Plaquemine culture mound site in Adams County, Mississippi inhabited from 1200 to 1700 CE."},{"src":"https://upload.wikimedia.org/wikipedia/commons/e/e9/Serpent_Mound_%28aerial_view%29.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail_unscaled","page":"https://commons.wikimedia.org/wiki/File:Serpent_Mound_(aerial_view).jpg","title":"Serpent Mound (aerial view).jpg","lic":"CC BY 2.5","licurl":"https://creativecommons.org/licenses/by/2.5","by":"Timothy A. Price and Nichole I.; uploaded by the authors.","cap":"View of the The Great Serpent Mound, one of the most important prehistoric effigy mound od Adema Culture, located on the Ohio river, Ohio, USA."},{"src":"https://thumb.wikimedia.org/wikipedia/commons/thumb/3/31/Serpent_Mound_Plaque.jpg/1280px-Serpent_Mound_Plaque.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail","page":"https://commons.wikimedia.org/wiki/File:Serpent_Mound_Plaque.jpg","title":"Serpent Mound Plaque.jpg","lic":"CC BY-SA 3.0","licurl":"https://creativecommons.org/licenses/by-sa/3.0","by":"Stepshep","cap":"Image of the w:Serpent Mound plaque"}]},"img":null,"md":null,"hh":[{"v":"300 BCE","h":"Built by the Adena, per 2014 radiocarbon dating","s":[126]},{"v":"c.300 BCE","u":"text","h":"14C date","s":[127]},{"v":"Clay, quartz","h":"Made of","s":[126]}],"hs":{"126":["Wikipedia: Serpent Mound (and sources cited there)","https://en.wikipedia.org/wiki/Serpent_Mound"],"127":["Wikipedia Serpent Mound","https://en.wikipedia.org/w/index.php?title=Serpent_Mound&oldid=1378361562"]},"lh":{"s":"img/h/NAM-013.webp","w":960,"h":639,"o":"https://upload.wikimedia.org/wikipedia/commons/3/31/Serpent_Mound%2C_Peebles%2C_Ohio_04.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail_unscaled"}}