Unlike others Angkor temples, Angkor Wat is oriented towards the West. Although Cambodia is a Buddhist nation, Angkor Wat was originally constructed as a Hindu temple dedicated to god Vishnu. The reason Angkor Wat oriented to the West is still debated, but many people believe that because Vishnu, a supreme god head, is facing west, people who want to visit him should come from east, that's why the entrance placed west.
Another reason that gets supported by other people is Angkor Wat may have been built as a tomb for king Suryasvarman II (who built it), not as a temple. That's why it faces west, because the West represents death in many religions. Unfortunately, when Suryavarman II died and where he was buried still remain unknown to us, but one thing for sure, the temple wasn't finished until after his vanishing from the historical record.
Whatever the reason, the fact remains that Angkor Wat facing west makes sunrise at this place become an iconic travel sunrise. Being at Angkor Wat while it's still dark and waiting for the sun rising gradually behind the largest religious monument in the world, with birds flying around the towers is definitely a special experience, and it's absolutely splendid.