Wat Phra Phai Luang is the largest temple outside the city walls, and is second only to Wat Mahathat in size. In fact, the temple is older than the city, and was most likely built late in the twelfth century during the reign of the great Khmer king, Jayavarman VII (the king who had Angkor Thom built).
While the temple was obviously quite large and imposing in its day, you need to use a lot of imagination to see what it must have been like. The plan must have been a bit haphazard even when the temple was in active use, having grown and changed over many centuries, and now it is a jumble of scattered stones and bricks. Like most Buddhist temples, the buildings are aligned on an east-west axis, with the major images facing east.
Near the eastern-most end of the main grouping are the barely recognizable remains of a large reclining Buddha. Behind this is a large mondop with monumental Buddha images on each of its four sides. Next in line are the remains of the main prayer hall, which back directly up against three large Khmer style prangs aligned north to south. Only one of the towers still remains largely intact, with some rather intricate details.