Preah Khan of Kompong Svay

The archeological complex of Preah Khan Kampong Svay (Khmer: ព្រះខ័ននៅកំពង់ស្វាយ), also known as Prasat Bakan (according to local pronunciation), or Bakan Svay Rolay, is located 100 km east of Angkor, in the Preah Vihear province of Cambodia. It stands as the largest single religious complex ever built during the Angkorian Era, as its exterior enclosure is over 22 km square, even if the isolated location makes it one of the less-visited Angkorian sites.

Archaeological site data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).