Prang Sam Yot / The Monkey Temple

As well known for its resident monkeys as its looming towers, this is Lopburi's most famous attraction. The three linked towers were built from laterite and sandstone by the Khmer in the 13th century as a Mahayana Buddhist temple.

It was converted to Theravada Buddhism by King Narai in the 17th century. Two ruined, headless Buddha images are inside; a third, more complete Buddha sits photogenically in front of the central tower. 
The temple has been overrun by macaques. This may have started because of the annual Monkey Buffet Festival that occurs in the city, during which locals give them fruits and vegetables. Now the monkey population is over 2,000, and most of them live in the temple in relative isolation from the human population. However, living in such close quarters with humans has made them unafraid to snatch treats and personal belongings right out of your hands.