The most important building in a Wat is known as Bot.[214] It has a colonnade of pillars outside and is surmounted by three or four roofs, not much raised one above the other, and bearing finials of a curious shape, said to represent a snake’s head.[215] It is also marked off by a circuit of eight stones, cut in the shape of Bo-tree leaves, which constitute a sima or boundary.  It is in the Bot that ordinations and other acts of the Sangha are performed.  Internally it is a hall:  the walls are often covered with paintings and at the end there is always a sitting figure of the Buddha[216] forming the apex of a pyramid, the lower steps of which are decorated with smaller images and curious ornaments, such as clocks under glass cases.

Siamese images of the Buddha generally represent him as crowned by a long flame-like ornament called Siro rot,[217] probably representing the light supposed to issue from the prominence on his head.  But the ornament sometimes becomes a veritable crown terminating in a spire, as do those worn by the kings of Camboja and Siam.  On the left and right of the Buddha often stand figures of Phra:  Mokha:  la (Moggalana) and Phra:  Saribut (Sariputta).  It is stated that the Siamese pray to them as saints and that the former is invoked to heal broken limbs.[218] The Buddha when represented in frescoes is robed in red but his face and hands are of gold.  Besides the Bot a Wat contains one or more wihans.  The word is derived from Vihara but has come to mean an image-house.  The wihans are halls not unlike the Bots but smaller.  In a large Wat there is usually one containing a gigantic recumbent image of the Buddha and they sometimes shelter Indian deities such as Yama.

In most if not in all Wat there are structures known as Phra:  chedi and Phra:  prang.  The former are simply the ancient cetiyas, called dagobas in Ceylon and zedis in Burma.  They do not depart materially from the shape usual in other countries and sometimes, for instance in the gigantic chedi at Pra Pratom, the part below the spire is a solid bell-shaped dome.  But Siamese taste tends to make such buildings slender and elongate and they generally consist of stone discs of decreasing size, set one on the other in a pile, which assumes in its upper parts the proportions of a flagstaff rather than of a stone building.  The Phra:  prangs though often larger than the Phra:  chedis are proportionally thicker and less elongate.  They appear to be derived from the Brahmanic temple towers of Camboja which consist of a shrine crowned by a dome.  But in Siam the shrine is often at some height above the ground and is reduced to small dimensions, sometimes becoming a mere niche.  In large Phra:  prangs it is approached by a flight of steps outside and above it rises the tower, terminating in a metal spire.  But whereas in the Phra:  chedis these spires are simple, in the Phra:  prangs they bear three crescents representing the trident of Siva and appear like barbed arrows.  A large Wat is sure to contain a number of these structures and may also comprise halls for preaching, a pavilion covering a model of Buddha’s foot print, tanks for ablution and a bell tower.  It is said that only royal Wats contain libraries and buildings called chatta mukh, which shelter a four-faced image of Brahma.[219]