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Angkor Wat at late afternoon, Siem Reap
Angkor Wat at late afternoon, Siem Reap. Photo: Bjørn Christian Tørrissen · CC BY-SA 4.0 · via Wikimedia Commons
Ancient worlds · Khmer Empire · 9th–15th century CE

Angkor: The Hydraulic City

Established802 CE – 1431 CESiem Reap Province, Cambodia

The largest pre-industrial city on Earth, revealed by lasers through the jungle.

Research draft · editor review pending. Every claim below is linked to a checked source, but this dossier has not yet been reviewed by a human editor. Spot an error? Corrections are logged.

Angkor was the capital of the Khmer Empire, home to Angkor Wat and hundreds of other temples. Archaeological mapping, and then airborne LiDAR that sees through forest canopy, revealed that the temples sat within a vast urban landscape of roads, canals, reservoirs and rice fields covering at least 1,000 square kilometers.

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How to read the labels

EstablishedSupported by strong, converging evidence.
ContestedEvidence exists but qualified scholars disagree.
UnresolvedThe question is open; evidence does not settle it.
LegendComes from myth, literature or tradition, not physical evidence.
SpeculativeA hypothesis with little direct evidence so far.

Hero image: Angkor Wat at late afternoon, Siem Reap. Photo: Bjørn Christian Tørrissen · CC BY-SA 4.0 · via Wikimedia Commons. Evidence labels describe the written claims, not the image. Version 1 · updated 2026-10-22.