This relief is one of many in the Terrace of the Leper King. Located in the Royal Square of the ancient Khmer city of Angkor Thom, it was built under King Jayavarman VII. I'm not sure how old the terrace is, but considering the time of Jayavarman VII's reign, and the age of other temples in the area, it's likely around 800 years old.
While some detail has definitely been lost to time, it's still really impressive just how much effort was put in. This is just one of many many other reliefs at the site. When you walk around, it's easy to lose sight of the sweat and labor that must have gone into constructing the site, as it's old and no longer at its former glory. Looking back and reflecting on it later, however, I'm impressed.
Relief sculpture from the Terrace of the Leper King.