A silent contemplation, prayer, and reflection as a gesture of respect in mourning of the dead who lost their lives in tragic historic event. Watching A commemorative stupa filled with skulls and bones of victims at the killing fields of Choeung Ek. There a number of sites in Cambodia where collectively more than a million people were killed and buried by the Khmer Rouge regime, during its rule of the country from 1975 to 1979.