Cambodia’s capital and largest city is located on the banks of the Mekong river. Not many cities have a history like Phnom Penh, making it an interesting stop on your itinerary nowadays. The buildings of a highschool were turned into the Khmer Rouge’s S-21 detention and torture center in the 1970’s. Today it houses the Tuol Sleng Museum of Genocide Crimes with exhibits and photographs. A short drive southwest of Phnom Penh are the Killing Fields of Choeung Ek. More than 17,000 victims were killed and buried in mass grave.