Fact Check Index

Every Fact Check we have published, in one place. Each card shows the claim we checked, the verdict we reached and the sources behind it. Pick a verdict below, or filter by topic and region.

9 Fact Checks so far. Labels apply to claims, not to whole articles, and can change when new research is published. How we check evidence

Established Ancient Technology Europe

30 Surviving Gears Show the Antikythera Mechanism Was an Ancient Analog Computer

Claim checked The Antikythera mechanism was an ancient analog computer

By Aris Manus ·

Part verdicts (6)
  • Established The Antikythera mechanism was an ancient analog computer, a hand-cranked bronze calculator that predicted eclipses
  • Unverified Its gearing showed the positions of all five planets known in antiquity
  • Disputed The mechanism made precise astronomical predictions in practice
  • Established The calendar ring was laid out for a lunar year of about 354 days rather than the 365-day Egyptian year
  • Unverified The mechanism was built around 205 BC
  • Fringe Aliens or time travelers supplied the technology
Sources (11)
  1. Freeth, Tony, et al. (2021). A Model of the Cosmos in the ancient Greek Antikythera Mechanism. Scientific Reports 11: 5821. Read in full
  2. Freeth, Tony, et al. (2006). Decoding the ancient Greek astronomical calculator known as the Antikythera Mechanism. Nature 444: 587 to 591. Abstract and editors' summary only
  3. Woan, Graham, and Joseph Bayley (2024). An improved calendar ring hole-count for the Antikythera mechanism. Horological Journal, July 2024, arXiv version. Read in full
  4. University of Glasgow (2024). Press release on the calendar ring study, June 27, 2024. Read in full
  5. Szigety, Esteban Guillermo, and Gustavo Francisco Arenas (2025). The Impact of Triangular-Toothed Gears on the Functionality of the Antikythera Mechanism. arXiv preprint. Read in full
  6. Carman, Christian C., and James Evans (2014). On the epoch of the Antikythera mechanism and its eclipse predictor. Archive for History of Exact Sciences 68. Abstract only
  7. Iversen, Paul A. (2017). The Calendar on the Antikythera Mechanism and the Corinthian Family of Calendars. Hesperia 86. Abstract only
  8. Voulgaris, Aristeidis, Christophoros Mouratidis and Andreas Vossinakis (2023). The Initial Calibration Date of the Antikythera Mechanism after the Saros spiral mechanical Apokatastasis. Almagest 14. Abstract only
  9. Cicero. On the Republic, Book 1, sections 21 and 22, translated by Clinton W. Keyes (1928). Read in full (passage)
  10. Science Museum Group. Byzantine sundial-calendar, object 1983-1393. Read in full
  11. Dunning, Brian (2009). The Antikythera Mechanism. Skeptoid, episode 184. Read in full
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Unverified Lost CivilizationsPrehistory and Megaliths Asia

27,000-Year-Old Pyramid Claim at Gunung Padang Rests on Retracted Soil Dates

Claim checked Gunung Padang is a pyramid built 20,000 to 27,000 years ago

By Aris Manus ·

Part verdicts (6)
  • Established Gunung Padang is a megalithic site of five stone terraces on a hilltop in Cianjur, West Java, described by Dutch scholars more than a century ago
  • Established Charcoal found beneath terrace retaining walls dates to around 117 BC and 50 BC
  • Established The 2023 pyramid paper was retracted on March 18, 2024
  • Unverified Gunung Padang is a pyramid built 20,000 to 27,000 years ago
  • Unverified Large chambers lie inside the hill
  • Unverified An advanced Ice Age civilization, later wiped out, built the site
Sources (7)
  1. Natawidjaja, Danny Hilman, et al. (2023). Geo-archaeological prospecting of Gunung Padang buried prehistoric pyramid in West Java, Indonesia. Archaeological Prospection (retracted). Read in full
  2. Archaeological Prospection (2024). Retraction: Geo-Archaeological prospecting of Gunung Padang buried prehistoric pyramid in West Java, Indonesia. Volume 31, Issue 2. Read in full
  3. Powell, Eric A. (2024). Java's Megalithic Mountain. Archaeology, July/August 2024. Read in full
  4. Lewis, Dyani (2023). Experts Doubt Claims that World's Oldest Pyramid Was Discovered in Indonesia. Scientific American, reprinted from Nature, November 28, 2023. Read in full
  5. Grove, Jack (2024). Paper claiming world's oldest pyramid retracted over error. Times Higher Education. Read in full
  6. Natawidjaja, Danny Hilman, et al. (2024). Authors' response to the retraction, posted March 21, 2024. grahamhancock.com. Read in full
  7. Netflix (2022). Ancient Apocalypse, Season 1, episode listing. Read in full (listing only)
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Disputed Prehistory and MegalithsMyths and Legends Europe

Did Stonehenge's stones really come from Wales and Scotland? Fact check

Claim checked Stonehenge's stones were brought from Wales and Scotland by people, and Merlin or giants had nothing to do with it.

By Aris Manus ·

Part verdicts (5)
  • Established Many bluestones came from the Preseli Hills in Wales, and the Altar Stone from north-east Scotland
  • Disputed Whether people or glacier ice moved the bluestones about 230 km, and whether Waun Mawn was an earlier circle
  • Unverified How the Altar Stone traveled about 700 to 750 km
  • Established The story of Merlin and the giants is medieval folklore, first written down about 1136
  • Fringe Giants, wizards or alien help moved the stones
Sources (22)
  1. Parker Pearson, M. et al. (2015). Craig Rhos-y-felin: a Welsh bluestone megalith quarry for Stonehenge. Antiquity 89: 1331 to 1352. Read in full
  2. Parker Pearson, M. et al. (2019). Megalith quarries for Stonehenge's bluestones. Antiquity 93: 45 to 62. Read in full
  3. Parker Pearson, M. et al. (2021). The original Stonehenge? A dismantled stone circle in the Preseli Hills of west Wales. Antiquity 95: 85 to 103. Read in full, post-referee version
  4. Darvill, T. (2022). Mythical rings? Waun Mawn and Stonehenge Stage 1. Antiquity 96: 1515 to 1529. Read in full
  5. Parker Pearson, M. et al. (2022). How Waun Mawn stone circle was designed and built, and when the Bluestones arrived at Stonehenge: a response to Darvill. Antiquity 96: 1530 to 1537. Read in full, accepted manuscript
  6. John, B. S. (2024). The Stonehenge bluestones did not come from Waun Mawn in West Wales. The Holocene 34: 895 to 907. Abstract only
  7. Kellaway, G. A. (1971). Glaciation and the Stones of Stonehenge. Nature 233: 30 to 35. Journal page summary only
  8. John, B. S. (2024). A bluestone boulder at Stonehenge: implications for the glacial transport theory. E&G Quaternary Science Journal 73: 117 to 134. Read in full
  9. Bevins, R. E. et al. (2025). The enigmatic 'Newall boulder' excavated at Stonehenge in 1924: New data and correcting the record. Journal of Archaeological Science: Reports. Abstract only
  10. Clarke, A. J. I. and Kirkland, C. L. (2026). Detrital zircon-apatite fingerprinting challenges glacial transport of Stonehenge's megaliths. Communications Earth and Environment 7: 54. Read in full
  11. Clarke, A. J. I. and Kirkland, C. L. (2026). Grains of sand prove people, not glaciers, transported Stonehenge rocks. The Conversation, 21 January 2026. Read in full
  12. Clarke, A. J. I. et al. (2024). A Scottish provenance for the Altar Stone of Stonehenge. Nature 632: 570 to 575. Read in full
  13. Bevins, R. E. et al. (2024). Was the Stonehenge Altar Stone from Orkney? Journal of Archaeological Science: Reports 58: 104738. Read in full
  14. Parker Pearson, M. et al. (2025). Stonehenge and its Altar Stone: the significance of distant stone sources. Archaeology International 27. Abstract only
  15. Clarke, A. J. I., Veness, R., Kirkland, C. L. et al. (2026). From Highlands to Henge: Refining the Provenance and Transport Pathways of Stonehenge's Altar Stone. Journal of Quaternary Science 41: 888 to 895. Abstract only
  16. Veness, R. (2026). New theory on how six-tonne Stonehenge rock was transported from Scotland thousands of years ago by a glacier. The Conversation, 28 July 2026. Read in full
  17. Nash, D. J. et al. (2020). Origins of the sarsen megaliths at Stonehenge. Science Advances 6: eabc0133. Read in full
  18. Hancock, R. G. V. et al. (2024). Stonehenge revisited: A geochemical approach to interpreting the geographical source of sarsen stone #58. Archaeometry 67: 1 to 19. Abstract only
  19. Nash, D. J. and Ciborowski, T. J. R. (2025). Comment on: 'Stonehenge revisited...'. Archaeometry 67: 1423 to 1436. Abstract only
  20. Hancock, R. G. V. et al. (2025). On Sourcing Stonehenge Sarsen Stone #58: A Response to Nash and Ciborowski's Comments. Archaeometry 68: 48 to 50. Abstract only
  21. English Heritage. Set in Stone? Stonehenge history and stories. Read in full
  22. Geoffrey of Monmouth (c. 1136). History of the Kings of Britain, Book 8, chapters 10 to 12, trans. A. Thompson and J. A. Giles (1842). Read in full
Read the Fact Check
Fringe Lost CivilizationsPrehistory and Megaliths Worldwide

Did a comet end the Ice Age and wipe out a civilization? Fact check

Claim checked Did a comet end the Ice Age and wipe out a civilization?

By Aris Manus ·

Part verdicts (5)
  • Established A sharp cold spell began about 12,900 years ago, with a platinum spike in Greenland ice at its start
  • Disputed A comet impact or airburst caused the cold spell, wildfires and extinctions
  • Disputed The Abu Hureyra meltglass was made by a cosmic event
  • Fringe The comet ended the Ice Age
  • Unverified An advanced civilization was wiped out at that time
Sources (15)
  1. Rasmussen, S. O. et al. (2006), "A new Greenland ice core chronology for the last glacial termination", Journal of Geophysical Research 111, D06102. Read in full
  2. Firestone, R. B. et al. (2007), "Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling", PNAS 104 (41): 16016 to 16021. Read in full
  3. Wolbach, W. S. et al. (2018), "Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ~12,800 Years Ago. 1. Ice Cores and Glaciers", Journal of Geology 126 (2): 165 to 184. Read: abstract only
  4. Wolbach, W. S. et al. (2018), part 2, "Lakes, Marine Cores, and Terrestrial Sequences", Journal of Geology 126 (2): 185 to 205. Read in full
  5. Petaev, M. I. et al. (2013), "Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas", PNAS 110 (32): 12917 to 12920. Read: abstract only
  6. Moore, A. M. T. et al. (2020), "Evidence of Cosmic Impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C", Scientific Reports 10: 4185. Read in full
  7. Correction to Moore et al. (2020), Scientific Reports 15: 40645, published 19 November 2025. Read in full
  8. Holliday, V. T. et al. (2014), "The Younger Dryas impact hypothesis: a cosmic catastrophe", Journal of Quaternary Science 29 (6): 515 to 530. Read: abstract only
  9. Holliday, V. T. et al. (2023), "Comprehensive refutation of the Younger Dryas Impact Hypothesis (YDIH)", Earth-Science Reviews 247: 104502. Read: abstract only
  10. Sweatman, M. B., Powell, J. L. and West, A. (2024), "Rejection of Holliday et al.'s alleged refutation of the Younger Dryas impact hypothesis", Earth-Science Reviews 258: 104960. Read: abstract only
  11. Retraction notice, PLOS One, 11 February 2026, "A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay". Read in full
  12. Retraction notice, PLOS One, 11 February 2026, "Shocked quartz at the Younger Dryas onset (12.8 ka) supports cosmic airbursts/impacts contributing to North American megafaunal extinctions and collapse of the Clovis technocomplex". Read in full
  13. Retraction Watch (4 March 2026), "Controversial comet theory struck by two new retractions". Read in full
  14. Graham Hancock, book page for America Before (2019), grahamhancock.com. Read in full
  15. Society for American Archaeology, open letter to Netflix and ITN, 30 November 2022, signed by Daniel H. Sandweiss. Read in full
Read the Fact Check
Fringe Ancient EgyptAncient Aliens and UFOs Africa

Did aliens build the pyramids? Fact check

Claim checked Did aliens build the pyramids?

By Aris Manus ·

Part verdicts (5)
  • Established Egyptians of the Fourth Dynasty built the Giza pyramids as a state project
  • Fringe Aliens built the pyramids
  • Unverified A lost civilization built or designed them
  • Disputed How the blocks were raised to the upper levels
  • Disputed How many people worked on the Great Pyramid
Sources (9)
  1. Tallet, P. (2017). Les papyrus de la mer Rouge I. Le "journal de Merer" (Papyrus Jarf A et B). MIFAO 136. Cairo: Institut français d'archéologie orientale. Publisher's open PDF read (summary, contents and Annexe I, the English translation with summary and
  2. Ancient Egypt Research Associates. "The Lost City of the Pyramids (Heit el-Ghurab)." Project page. Read in full
  3. Van De Mieroop, M. (2020). "Building in the High Desert: the Great Pyramid of Giza." Groniek 225: 391 to 403. Read in full
  4. Dash, G. (2013). "How the Pyramid Builders May Have Found Their True North." AERAGRAM 14 (1): 8 to 14. Read in full
  5. Sheisha, H. et al. (2022). "Nile waterscapes facilitated the construction of the Giza pyramids during the 3rd millennium BCE." PNAS 119 (37): e2202530119. Read in full (Europe PMC copy)
  6. Ghoneim, E. et al. (2024). "The Egyptian pyramid chain was built along the now abandoned Ahramat Nile Branch." Communications Earth and Environment 5: 233. Abstract and results read
  7. Jackson, K. (2011). "A Short History of Pyramidology." BBC History, last updated 17 February 2011. Read in full
  8. Epstein, S. M. (1987). "Scholars Will Call it Nonsense: The Structure of Erich von Däniken's Argument." Expedition 29 (2). Penn Museum. Opening section read
  9. von Däniken, E. (1968). Erinnerungen an die Zukunft. English edition: Chariots of the Gods? Unsolved Mysteries of the Past. Translated by Michael Heron. London: Souvenir Press, 1969. Bibliographic record only
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Unverified Empires and Rulers Africa

$400 Billion Mansa Musa Fortune Traces to a 2012 Website List

Claim checked Mansa Musa was the richest person who ever lived, worth an inflation-adjusted $400 billion, and his spending in Cairo on his 1324 hajj crashed the price of gold, or Egypt's economy, for 12 years.

By Aris Manus ·

Part verdicts (6)
  • Established Mansa Musa made the hajj in 1324, passed through Cairo, and gave away and spent large amounts of gold there
  • Established Gold fell in value against silver in Cairo after his visit
  • Disputed The low gold price lasted about twelve years
  • Unverified His spending crashed or wrecked Egypt's economy
  • Unverified He was worth $400 billion
  • Unverified He was the richest person who ever lived
Sources (7)
  1. al-Umari, trans. J.F.P. Hopkins, in Levtzion and Hopkins (1981). Corpus of Early Arabic Sources for West African History, pp. 269 to 273, excerpt. Digital History, University of Houston. Read in full (excerpt)
  2. Ibn Battuta, trans. H.A.R. Gibb (1929). Travels in Asia and Africa 1325 to 1354, Mali section. Fordham Internet Medieval Sourcebook. Read in full (Mali section)
  3. Schultz, Warren C. (2006). Mansa Musa's Gold in Mamluk Cairo: A Reappraisal of a World Civilizations Anecdote. In Post-Mongol Central Asia and the Middle East: Studies in History and Historiography in Honor of Professor John E. Woods. Read in full
  4. Montagne, Renee (2012). Who's The Richest Person In History? NPR Morning Edition. Read in full
  5. Ortiz, Erik (2012). King Mansa Musa of Mali named richest person of all time. New York Daily News. Read in full
  6. Davidson, Jacob (2015). The 10 Richest People of All Time. Money. Read in full
  7. Mohamud, Naima (2019). Is Mansa Musa the richest man who ever lived? BBC News. Read in full
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Unverified Lost CivilizationsMyths and Legends Europe

Was Atlantis a real place? Fact check

Claim checked Was Atlantis a real place?

By Aris Manus ·

Part verdicts (5)
  • Unverified Atlantis was a real place. Plato is our only source, and no site has been found
  • Disputed Atlantis is Plato's invention. Most classicists we consulted think so
  • Fringe A continent sank in the Atlantic. Geologists tested this and found no sign of it
  • Fringe The Richat Structure in Mauritania. NASA describes it as a natural dome shaped by erosion
  • Unverified Thera and the Minoans, Doñana, Malta, other African sites and Antarctica
Sources (10)
  1. Plato. Timaeus. Translated by Benjamin Jowett. Project Gutenberg eBook 1572. Atlantis passages and Jowett's introduction read
  2. Plato. Critias. Translated by Benjamin Jowett. Project Gutenberg eBook 1571. Atlantis narrative and Jowett's introduction read
  3. Liverpool University Press (2018). "The 'truth' behind Atlantis: Christopher Gill on Plato's Atlantis Story." Interview, 29 August 2018. Read in full
  4. Frost, K. T. (1913). "The Critias and Minoan Crete." Journal of Hellenic Studies 33: 189 to 206. Read in full (scan of the journal volume, Internet Archive)
  5. Tschoegl, N. (1972). "Atlantis: Cradle of Western Civilization?" Engineering and Science 35 (7), California Institute of Technology, June 1972. Read in full
  6. Friedrich, W. L., Kromer, B., Friedrich, M., Heinemeier, J., Pfeiffer, T. and Talamo, S. (2006). "Santorini eruption radiocarbon dated to 1627-1600 B.C." Science 312 (5773): 548. Abstract read
  7. Pearson, C. L., Brewer, P. W., Brown, D., Heaton, T. J., Hodgins, G. W. L., Jull, A. J. T., Lange, T. and Salzer, M. W. (2018). "Annual radiocarbon record indicates 16th century BCE date for the Thera eruption." Science Advances 4: eaar8241. Read in full
  8. Kühne, R. W. (2004). "A location for 'Atlantis'?" Antiquity 78 (300), Project Gallery: 1 to 4. Read in full
  9. Schuchert, C. (1917). "Atlantis and the Permanency of the North Atlantic Ocean Bottom." Proceedings of the National Academy of Sciences 3 (2): 65 to 72. Read in full (scan of the journal issue, Internet Archive)
  10. NASA Earth Observatory (2022). "The Eye of the Sahara." Image of the Day, 10 July 2022. Read in full
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Unverified Prehistory and Megaliths Asia

Is Göbekli Tepe the world's oldest temple? Fact check

Claim checked Is Göbekli Tepe the world's oldest temple?

By Aris Manus ·

Part verdicts (3)
  • Established Age (about 9600 to 8200 BCE)
  • Disputed Temple with no settlement
  • Unverified World's oldest temple
Sources (6)
  1. UNESCO World Heritage Centre. "Göbekli Tepe." Property 1572, inscribed 2018. Listing page, including the statement of Outstanding Universal Value. Read in full
  2. Clare, L. (2020). "Göbekli Tepe, Turkey. A brief summary of research at a new World Heritage Site (2015 to 2019)." e-Forschungsberichte des DAI 2020 (2): 81 to 88. Read in full
  3. Schmidt, K. (2010). "Göbekli Tepe: the Stone Age Sanctuaries. New results of ongoing excavations with a special focus on sculptures and high reliefs." Documenta Praehistorica 37: 239 to 256. Read in full
  4. Dietrich, L., Meister, J., Dietrich, O., Notroff, J., Kiep, J., Heeb, J. et al. (2019). "Cereal processing at Early Neolithic Göbekli Tepe, southeastern Turkey." PLOS ONE 14 (5): e0215214. Read in full
  5. Dietrich, O., Heun, M., Notroff, J., Schmidt, K. and Zarnkow, M. (2012). "The role of cult and feasting in the emergence of Neolithic communities. New evidence from Göbekli Tepe, south-eastern Turkey." Antiquity 86 (333): 674 to 695. Journal summary read
  6. Banning, E. B. (2011). "So Fair a House: Göbekli Tepe and the Identification of Temples in the Pre-Pottery Neolithic of the Near East." Current Anthropology 52 (5): 619 to 660. Abstract read
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Fringe Ancient EgyptLost Civilizations Africa

Was the Sphinx built 10,000 years ago? Fact check

Claim checked Was the Sphinx built 10,000 years ago?

By Aris Manus ·

Part verdicts (1)
  • Fringe Was the Sphinx built 10,000 years ago?
Sources (12)
  1. Lehner, M. "Who Built the Sphinx? The Sphinx Temple Has the Answer." Ancient Egypt Research Associates (AERA)
  2. AERA. "Khafre's Monuments as a Unit."
  3. AERA. "Geology of the Sphinx."
  4. Hawass, Z. and Lehner, M. (1994). "The Sphinx: Who built it, and why?" Archaeology 47 (5): 30 to 41. Bibliographic record checked
  5. Schoch, R. M. "The Great Sphinx." Research highlights page
  6. KMT, Vol. 5 No. 2 (1994), contents listing Harrell's article. Schoch, R. M. (1992), "Redating the Great Sphinx of Giza", KMT 3 (2), is cited from Harrell and AERA and was not read directly
  7. Harrell, J. A. (1994). "The Sphinx Controversy: Another Look at the Geological Evidence." KMT 5 (2): 70 to 74. Reproduced on Hall of Ma'at
  8. Harrell, J. A. (2002). "Comments on the Geological Evidence for the Sphinx's Age." Hall of Ma'at
  9. Reader, C. D. (2001). "A Geomorphological Study of the Giza Necropolis, with Implications for the Development of the Site." Archaeometry 43 (1): 149 to 165. Abstract read
  10. Dye, L. (1991). "Sphinx's New Riddle: Is It Older Than Experts Say?" Los Angeles Times, 23 October 1991
  11. Hancock, G. and Bauval, R. Keeper of Genesis / The Message of the Sphinx. Book page, Graham Hancock official website
  12. Fairall, A. (1999). "Precession and the layout of the ancient Egyptian pyramids." Astronomy and Geophysics 40 (3): 3.4
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