The ancient Cambodian capital of Angkor Wat, had a staggering 900,000 inhabitants before it was abandoned in 1431, according to a new study. An international team, led by the University of British Columbia, examined three decades of data to create a demographic model of the Medieval city. Their model revealed that the capital of the long-gone Khmer Empire housed between 700,000 and 900,000 people during its zenith in the 13th century.