616Early 7th century; capital under Isanavarman I (c. 616–637) · Sambor Prei Kuk, Kampong Thom province

Isanapura (Sambor Prei Kuk), capital of Chenla

A brick tower sanctuary at Sambor Prei Kuk, with stone lions guarding its doorway, in dry forest — Photo: PsamatheM. CC BY-SA 4.0, via Wikimedia Commons

Before Angkor, the Khmer kingdom of Chenla was ruled from Isanapura, the royal city that Isanavarman I made his capital in the early 7th century near today's Kampong Thom. Its dry forest holds well over a hundred brick sanctuaries, some of them octagonal, with carved 'flying palace' panels. The site shows Khmer temple building in its formative stage and became a World Heritage Site in 2017.