Bayon Temple is well know for the many (216 actually) smiling faces adorning the temple.
I was living in Siem Reap for a few months and took these photos during a bike trip from the city to visit the temples. It is a nice bike ride (very flat the entire time). You can also rent tuk-tuks or taxis to tour the sites (I have done that also). I most enjoyed biking myself around. If I remember right it is between 12 and 20 km journey depending on what you decide to see and where start from in Siem Reap.
Bayon temple was built in the late 12th or early 13th century as the official state temple of the Mahayana Buddhist King Jayavarman VII.
Bayon stands at the centre of Jayavarman’s capital, Angkor Thom. Following Jayavarman’s death, it was modified and augmented by later Hindu and Theravada Buddhist kings in accordance with their own religious preferences.
This photo I took on a separate visit.
Bayon was the last state temple to be built at Angkor, and the only Angkorian state temple to be built primarily as a Mahayana Buddhist shrine dedicated to the Buddha, though a great number of minor and local deities were also encompassed as representatives of the various districts and cities of the realm.
Related: Bayon on Wikipedia – Ta Prohm temple, Angkor – Angkor Wat – Neak Poan Temple, Siem Reap, Cambodia – Borobudur in Java, Indonesia (Buddhist temple built in the 9th century)