From the plain below, Phnom Sampeau (also known as Phnom Sampov) can be seen at right. The smaller hill to the left is Krapeu mountain. Ongoing fighting between the Khmer Rouge, Government, and Vietnam forces occured in this area, and naturally, the high ground commands significance to this day.

Some portions of the cave complex are perhaps best known as the Killing Caves. The Khmer Rouge executed thousands of people on Phnom Sampeou, and many were thrown through openings near the top of the mountains and left to die a slow death in the cold and dark.

Vietnamese forces eventually dislodged the Khmer Rouge from power in 1979; however, guerrilla bands loyal to the KR continued to battle the central government well into the late 1990s.