Which ancient structure is the largest religious monument in the world?

Angkor Wat is the largest religious monument in the world.

The temple complex was built in the early 12th century by Khmer King Suryavarman II in what is now Cambodia. It was originally dedicated to the Hindu god Vishnu, unlike many later Khmer temples that were associated primarily with Buddhism. Its towers, galleries, bas-reliefs, and enormous surrounding moat reflect the power and engineering skill of the Khmer Empire.

Angkor Wat gradually became a Buddhist sanctuary and remains an important place of worship. Its central quincunx of towers is designed to evoke Mount Meru, the cosmic mountain in Hindu and Buddhist traditions. Detailed carvings depict scenes from epics, royal life, and religious mythology.

Borobudur is another immense religious monument, but it is a Buddhist complex in Indonesia. The Parthenon and Karnak are also famous ancient sacred sites, yet neither matches Angkor Wat’s overall monumental scale.