Angkor Wat

Angkor Wat is the largest religious monument in the world — a 12th-century Hindu temple complex covering 162.6 hectares that was built by King Suryavarman II as his state temple and eventual mausoleum, and whose five lotus-bud towers have become the symbol of Cambodia (they appear on the national flag). The temple is oriented to the west (unusual for Hindu temples, which typically face east), and the sunrise over the towers, reflected in the moat that surrounds the complex, is one of the most photographed moments in Asia.

The approach — a 250-metre stone causeway across the 200-metre-wide moat, through the western gopura (entrance gate), and along a 350-metre elevated walkway to the temple itself — is designed to overwhelm with scale before revealing detail. The bas-reliefs on the outer gallery walls, stretching for nearly 800 metres, depict scenes from Hindu mythology (the Churning of the Ocean of Milk, the Battle of Lanka) and historical events (Suryavarman II's military campaigns) in a continuous stone narrative that is the longest bas-relief in the world.

The central tower, reached by vertiginously steep stairs (a reconstruction of the original staircase provides a less terrifying alternative), provides a view across the temple's concentric galleries, the surrounding forest, and the plain that was once the capital of the Khmer Empire — a city of over a million people when London's population was 50,000. Angkor Wat has been in continuous use since the 12th century (it transitioned from Hindu to Buddhist worship in the 13th century), and the monks who maintain the temple today connect the site to a living religious tradition that most ruins have lost.