The Khmer empire lasted from 800-1200 AD. They conquered neighboring kingdoms and became the main power of the Southeast Asian mainland. The Khmer built their capital at Angkor, along with the structure known as Angkor W at. Angkor Wat is a massive city-temple complex that covers nearly a square mile. This temple is a symbolic mountain to Vishnu, showing a strong Indian influence. This Indian influence came from the trade between Khmer and India, also evident in the many art forms and religions still present in modern day. The Khmer also established elaborate waterways to irrigate their rice crops and to increase trade and commerce. This irrigation system allowed them to grow three to four times the rice as their ancestors.