Over time, the Khmer Kingdom began to face serious problems. One major issue was its water system. The canals and reservoirs that once helped grow rice became hard to maintain. Changes in climate brought strong floods and long droughts, which damaged farms and made it difficult to feed the large population.
The Khmer Kingdom also faced attacks from neighboring kingdoms. Powerful rivals from nearby regions fought for land and control of trade routes. Wars drained resources and weakened the empire. As fighting increased, people slowly left the city of Angkor, and the great temples were used less and less.
As Khmer power faded, new kingdoms rose nearby. In what is now Thailand, the Ayutthaya Kingdom became powerful and adopted many Khmer ideas, including temple designs and royal traditions. In the east, Đại Việt grew stronger and took control of lands once influenced by the Khmer.
Although the Khmer Kingdom fell, its art, religion, and building ideas lived on through these successor kingdoms, and the ruins of Angkor still show how great the empire once was.