Angkor Wat, Cambodia

In a unique jungle setting, not far from the city of Siem Reap, Angkor Wat is known for being the world's largest religious monument, but it is more than sheer size that makes this complex so interesting. The site was built by the Khmers in the 12th century, and the architecture is nothing less than stunning. The site has an intriguing mix of excavated and unexcavated temples in varying shapes, sizes, and states of decay, with some buildings taking on a mystical appearance as they're swallowed up by trees and roots. Huge stone carved faces peer out in all directions. Extensive and intricate bas-reliefs line the walls and doorways. Crumbling passageways and steep stone stairs call out for exploration. Before its fall in the 15th century, Angkor Wat was the largest city in the world. The complex is huge, and visitors may want to spend a couple of days taking in the site.