Skulls of the thousands of people massacred in Cambodia during the reign of the Khmer Rouge. This photo was taken in the Choeung Ek Killing Fields outside of Phnom Penh. Between 1975 and 1978, some 17,000 men, women, and children who had been detained and tortured in the infamous S-21 prison were sent to this extermination camp to be shot, or eaten to death.