Engineering before architecture
A baray is an artificial reservoir, built not by excavating a hole but by raising enormous earth embankments above the surrounding plain. Angkor has several, and they are arguably a greater feat than the temples: moving that quantity of earth by hand, and aligning it precisely, is a staggering undertaking.
What they were for is one of the long-running arguments in Angkorian scholarship. The likeliest answer is that they served several purposes at once — symbolic representation of the cosmic ocean, water management for a city of great size, and support for agriculture in a landscape with a long dry season.
The three great barays
The West Baray is the largest and the only one still holding water year-round — roughly eight kilometres by two. At its centre sits the West Mebon, a partly ruined eleventh-century temple that once held a monumental bronze reclining Vishnu, now in the National Museum in Phnom Penh. Local families swim and picnic along its southern shore at weekends.
The East Baray, or Yasodharatataka, was built under Yasovarman I around the end of the ninth century and is now entirely dry — you can drive across what was its floor. The East Mebon, a temple-mountain with fine stone elephants at its corners, stood on an island in the middle and now rises incongruously from farmland.
The Jayatataka, or North Baray, belongs to Jayavarman VII and holds Neak Pean, a small and beautiful island sanctuary of linked pools. It had been dry for centuries before water was returned to it.
Visiting
The West Baray is outside the ticketed zone and free to visit; the West Mebon requires a boat. The East Mebon and Neak Pean are on the grand circuit and need a valid Angkor pass.
Late afternoon at the West Baray, when the light goes gold over the water and the town comes out to swim, is one of the more enjoyable non-temple hours you can spend at Angkor.