Angkor was the largest pre-industrial city on Earth

Laser mapping in 2012 revealed that the Khmer capital of Angkor, home to Angkor Wat, sprawled across roughly 1,000 square kilometers of canals, reservoirs and suburbs. At its 12th-century peak it likely supported several hundred thousand people, making it the largest urban settlement in the pre-industrial world. Most of the city was built in wood and has vanished, leaving only its stone temples standing.

— Michael D. Coe, Angkor and the Khmer Civilization — Thames & Hudson, 2003
Go deeper: get the book →