Claimed by both countries because of a misdrawn French map (that went unchallenged by Thailand for decades), the temple was awarded to Cambodia in a 1962 World Court ruling. Thailand's bruised pride never healed. In June 2008, as the Cambodian government sought Unesco World Heritage status for the complex, a border conflict over 4.6 sq km of land in front of the temple flared and led to deadly clashes between the nations' armies and became a cause célèbre of Thailand's ultra-nationalists. The situation remains unresolved and Thailand has shut the border.
Be aware that landmines have been laid during the present conflict and others may remain from the Khmer Rouge era, so it's important not to stray from any well-worn path.