Final answer:
The Angkor state, central to the Khmer Empire, was established along a tributary of the Mekong River. The empire, recognized for its impressive bureaucracy, architecture, and hydraulic engineering, reached its zenith from 802 CE to 1431 CE, influencing much of Southeast Asia.
Step-by-step explanation:
The Angkor state arose along a tributary of the Mekong River. The magnificent city of Angkor served as the capital of the Khmer Empire, which thrived from 802 CE to 1431 CE, at its peak controlling much of Southeast Asia. This was an empire known for its sophisticated form of government, extensive infrastructure, and grand architectural achievements such as Angkor Wat, an immense temple complex dedicated to the Hindu god Vishnu, and later also reflecting Buddhist influence.
The Mekong River not only provided sustenance and transportation but also played a strategic role in the power and expansion of the Khmer Empire. Structures like the Bayon Temple in the capital city Angkor Thom, and other temples across the region, reflect the religious beliefs and the expansive control of the empire. The Angkor state's remarkable achievements in architecture, agriculture, and trade were closely linked to its geography, with the Mekong River being a vital lifeline, until its decline in the 15th century due to internal strife and external pressures.