Half an hour by motorcycle outside of Phnom Penh. A peaceful spot by the riverside. A place where fat lazy bees buzzed, and where crickets sawed songs in the grass. A dirt pathway wound through this scene. I followed it until I met with the overgrown pit of an exhumed grave, its sides eroded like elderly gums or the caved-in face of a hobo. There were dozens of them, choked with stagnant...