Angkor Thom is the next stop after Angkor Wat when entering the Angkor Archaeological Park from the south. It is distinguished by four main entry gates, one on each side (north, south east and west) of the Angkor Thom complex. The South Gate tends to be considered the main entrance because that is where the majority of visitors first enter. By 9:00am this south gate can have a lot of people.
The main attraction within Angkor Thom is Bayon Temple. Said to have 200 faces of a smiling Buddha. I haven’t counted them but there are a lot. Most situated on towers with a face looking in each direction. There are outer and inner galleries with carved bas-reliefs that are fairly well preserved and interesting. I went back a second time in the late afternoon to study these in a little more detail and escape the crowds.
As mentioned above, Bayon Temple is the main attraction and is the largest temple within Angkor Thom and the first you will come to when entering through the south gate. In order of ascending north, the next sites are Baphuon and Phimeanakas with the Terrace of the Elephants directly in front of these two.
North of this is Terrace of the Leper King and Preah Palilay. Across the road is the Prasats Sour Prat which is divided by a road that leads to the fifth gate, the Victory Gate. Continuing north on the west side of the main road is a tented area with many food vendors. Behind that is Preah Pithu Group.
This whole area has a lot of visitors. Most focus on Bayon Temple. I recommend getting there early, maybe 7am to get you photo with no people standing in front of everything.
My most recent trip was May 2015. During this trip I focused on less traveled to ruins as well as seeking out places for sunset and sunrise. As it turns out, the hidden benefit to this was that I avoided the crowds of people while still seeing the main attractions of Angkor Thom.
One morning I went to Bayon for the sunrise. I would do this again but only if there were clear skies. It gave me the opportunity to see the faces of Bayon with a slight glow. I was also able to explore the bas reliefs of the outer galleries with no one around to get in the way. This is the way to do it.
For the added ruins I went to in Angkor Thom, they were great. The first was Mangalartha, a small ruin down an unmarked dirt road as you exit via the Victory Gate. I also visited the East Gate of Angkor Thom. This is seldom visited because there is no through road at the gate, the road is rough and it is a state of being restored.