For more than 400 years Ayutthaya was the capital of Thailand. The Burmese army sacked and destroyed the city in the late 1700s. The remnants of the palace and countless wats (Thai temples) sat decaying for two centuries. The locals, who had established a new town a few kilometers away, were afraid of the ruins and the ghosts they held.
Ayutthaya is now a UNESCO World Heritage Site and the ruins form Ayutthaya Historical Park. The ruins make a great day trip from Bangkok and are easily accessible by organized tour or train.