Wat Phra Mahathat
Ayutthaya
Built in 1374 at the start of the Ayutthaya era, Wat Mahathat is an impressive temple ruin originally constructed to house Buddha relics that mysteriously appeared to an early Ayutthayan king. Although the Burmese destroyed much of the temple, it is a great place to experience an unusual feel of derelict simplicity. The temple's main 'prang' is surrounded by four smaller prangs and its architecture is strictly Khmer style. Most of its artefacts were moved to the Chao Sam Phraya National Museum, so aside from the building itself, there isn't much to see.
The temple is famed for Buddha images that have tree roots grown around them to startling effect.