The old Khmer kingdom, one of the great powers of south-east Asia, established its capital cities at Angkor in present-day Cambodia. Driven by spiritual devotion and architectural ambition, the skilled and war-like Khmer rulers built many temples here, some on a massive scale. Angkor Wat is the greatest of the Angkor temples. This immense and complex structure, built in the 12th century CE, serves as a testimony to the phenomenal achievements that can be spurred by religious passion. Angkor Wat was built to portray Hindu cosmology and includes an immense temple-mountain that represents the peaks of mythical Mount Meru - the home of Hindu gods. The temple is reflected in pools that may have represented the primeval ocean. Angkor Wat later became a Buddhist monastery. Nine centuries later, it remains the largest religious building in the world.