Which kingdom built the temple complex of Angkor Wat?

Angkor Wat was built in the first half of the twelfth century under the Khmer king Suryavarman II, and two things about it are odd for a Khmer temple. It is dedicated to Vishnu rather than Shiva, and it faces west rather than east - which, with the anticlockwise order of its narrative reliefs, is why many scholars read it as a funerary monument as well as a temple. The reliefs themselves run for hundreds of metres, including a forty-nine-metre panel of the churning of the sea of milk.

The scale is hard to convey. The outer wall encloses about 162 hectares, the moat is nearly two hundred metres wide, and the bas-reliefs run for the better part of a kilometre - among them a forty-nine-metre panel of gods and demons hauling on a serpent to churn the sea of milk. It was built in perhaps thirty years.

The real discovery came from the air. Airborne laser scanning in 2012 and 2015 stripped away the forest canopy and revealed that the temples sat inside an enormous low-density city - roads, ponds, house mounds and field systems spread over something like a thousand square kilometres, quite possibly the largest pre-industrial urban complex on Earth. It ran on water: a network of reservoirs and canals of great sophistication and, as tree-ring records of prolonged drought and violent monsoon suggest, great fragility. Angkor Wat is on the Cambodian flag, the only building on any national flag.