BAGAN, Myanmar — Fires, floods, treasure seekers and ficus trees have by turns withered this ancient royal capital, but in many ways it still looks as it might have eight centuries ago.

More than 2,200 tiered brick temples and shrines sprawl across an arid 26-square-mile plain on the eastern bank of the Irrawaddy River, remnants of a magnificent Buddhist city that reached its height in the 11th and 12th centuries.

These monuments, on a red-dirt plain thinly populated by monks and goat herders, are an unparalleled concentration of temple architecture, featuring sophisticated vaulting techniques not seen in other Asian civilizations and elaborate mural paintings whose counterparts have not survived well in India....