Of all the temples we visited in the Angkor Archaeological Park, including Angkor Wat, Bayon was my favorite. It's pretty awesome, as I hope you'll be able to see from my photos below!
Bayon was built in late 12th/early 13th century by King Jayavarman VII as a Buddhist temple, but was later modified to accommodate the beliefs of Hindu and Buddhist rulers... that seems to be the case with many of the temples in the park: back and forth.
Echoing the faces on the city walls of Angkor Thom, Bayon is literally covered in enormous carved stone faces: 216 of them! You can't see the from afar, but as you approach they start to appear on the towers of the upper levels:
From what I understand, there is a theory that the faces are King Jayavarman VII himself, one that purports they are bodhisattva, and one that they are both, since the Khmer king fancied himself both a god and a king.
So many faces!
The faces all have this sort of coy/content/serene smile/smirk... very Mona Lisa-esque (or is the Mona Lisa Bayon-esque?):
Our tour guide, bless his heart, was sooooo excited to take funny photos of us interacting with the Bayon faces. "Stand here, face this way," he would excitedly exclaim, "Give me your camera." He would take several shots, giggling the whole time:
More face shots:
More tour-guide arranged photo opps, these being slightly less successful than the first round:
More faces? Yes.
In addition to all the carved faces on the temple's top level, the lower levels have a series of very cool and very intricate bas relief carvings... some depicting everyday life during the Khmer empire (including war/battle scenes) and some depicting images of Hindu mythology.
Khmer army on the march:
This carving depicts a naval battle on Tonle Sap lake between the Khmer and Cham empires (remember Cham/Champa?), complete with soldier bodies falling into the ocean:
One of the mythological carvings below depicts a king wrestling a massive serpent (from whom he apparently contracted leprosy):
More battle/marching scenes, now with 100% more elephants!:
All in all, my favorite temple in Angkor. Something about those faces, looking at you around every corner. Eerie!