ANGKOR WAT
Angkor Wat is the by far the biggest religious monument in the world. Its interior is built like a physical depiction of a mandala, and it is modelled after Mount Meru, the home of the Hindu gods, towers made to represent the five peaks of Mount Meru. Angkor Wat was originally a Hindu temple, then converted into Buddhist temple. Also, many of the temples in Angkor worshipped Hindu gods like Shiva, who was the ‘protector’ god. That shows the syncretism with the original animistic beliefs of the people. Thus, Angkor provides clear, physical evidence that Hinduism and Buddhism were brought to the region by the Indians, and adopted by early Southeast Asian empires like the Khmer Empire.
This video mentions how Angkor Wat was built like Mount Meru, the home of the Hindu Gods, and mentions about the Hindu carvings and sanskrit inscriptions in the temple.
Do head over to exhibit 3, on the Theories of Indianisation.