Buddhist monks carry flags as they march through the gates of the Choeung Ek "Killing Fields" memorial, where the bodies of nearly 9,000 people killed by the Khmer Rouge were exhumed from mass graves, on the outskirts of Phnom Penh June 7, 2011. A large group of Buddhist monks and nuns from Cambodia, Thailand, Myanmar, Laos and Japan gathered at Choeung Ek to pray for peace and for those who have died in wars and natural disasters. REUTERS/Samrang Pring (CAMBODIA - Tags: RELIGION SOCIETY POLITICS)