3/11 may refer to:March 11, in month-day date notation 3 November, in day-month date notation 3rd Battalion, 11th Marines March, 11 A.D.; see AD 11 November, 3 A.D.; see AD 3 2011 Tōhoku earthquake and tsunami Fukushima Daiichi nuclear disaster, caused by the earthquake and tsunami 2004 Madrid train bombings