The Bayon was built nearly 100 years after Angkor Wat. The basic structure and earliest part of the temple are not known. Since it was located at the centre of a royal city it seems possible that the Bayon would have originally been a temple-mountain conforming to the symbolism of a microcosm of Mount Meru. The middle part of the temple was extended during the second phase of building. The Bayon of today belonging to the third and last phase of the art style.
The architectural scale and composition of the Bayon exude grandness in every aspects. Its elements juxtapose each other to create balance and harmony. Over 2000 large faces carved on the 54 tower give this temple its majestic character. The faces with slightly curving lips, eyes placed in shadow by the lowered lids utter not a word and yet force you to guess much, wrote P Jennerat de Beerski in the 1920s. It is generally accepted that four faces on each of the tower are images of the bodhisattva Avalokitesvara and that they signify the omnipresence of the king. The characteristics of this faces - a broad forehead, downcast eyes, wild nostrils, thick lips that curl upwards slightly at the ends-combine to reflect the famous 'smile of Angkor'.