Siem Reap is getting more and more popular as a resort destination because of it's proximity to the Angkor Temples. The most famous, Angkor Wat, is a impressive temple that encompasses thousands of feet of wall with intricate carvings depicting scenes of Hindu mythology. It is definitely a sight to behold, but try visiting during winter times, as the weather can get very hot and muggy.
You will see Ta Prohm temple, Bayon temple, Angkor Wat, Canoe Tour at Tonlesap.