Syrian civil war: Areas controlled by the Syrian opposition in Ghouta, Damascus, were attacked by rockets (launcher pictured) containing sarin, killing at least 281 people.
Six people were killed during an escape attempt and riot at San Quentin State Prison in California; the subsequent trial of six inmates was the longest in state history at the time.
South Vietnamese special forces loyal to Ngô Đình Nhu, the brother of President Ngô Đình Diệm, raided and vandalised Buddhist pagodas (one pictured) across the country, arresting thousands and leaving hundreds dead.
American physicist Harry Daghlian accidentally dropped a tungsten carbide brick onto a plutonium bomb core, exposing himself to neutron radiation and later becoming the first Manhattan Project fatality due to a criticality accident.