At the southeast edge of town lies the huge bell-shaped chedi of Wat Ya Chai Mongkon. The chedi was built in 1592 by one of Ayutthaya's greatest kings, Nareusan the Great, to commemorate a victory over the Burmese won in the same year. The temple itself was established earlier, in 1357, by King Ramathibodi as a meditation site for monks returning from pilgrimages to Sri Lanka.
The temple is still functioning, and has taken on a role as a museum about King Nareusan as well. A very modern building in the basic shape of a wiharn has been built behind the temple in a formal garden.
Like all the temples and palaces of Ayutthaya, the temple was sacked by the Burmese when they finally took Ayutthaya in 1767. Some of the smaller chedis in the outer courtyard were toppled, but the big chedi was just too big and is relatively undamaged. The ubosot (ordination hall) was set on fire so that today only the crooked walls remain.
A new ubosot has been built just inside the walls of the old one, although its not actually complete, as you can tell by looking at the bare concrete of the roof gables.
The big chedi sits in an inner courtyard now lined with modern Buddha images. You can climb up to the base of the bell shape for an excellent view across the flat landscape of Ayutthaya. On a good clear day you can see the prangs of Wat Phra Ram and Wat Ratburana.
In the remains of a small wiharn near the main entrance is a restored and whitewashed reclining Buddha. It was also built by King Nareusan for his own meditation purposes.