School children wearing padded hoods to protect them from falling debris walk on a playground during an earthquake simulation exercise at an elementary school in Tokyo March 11, 2015. The school in one of the central wards in Tokyo held an annual evacuation drill to prepare for earthquakes, on the fourth anniversary of the March 11, 2011 earthquake and tsunami that killed thousands and set off a nuclear crisis. REUTERS/Issei Kato (JAPAN - Tags: DISASTER ANNIVERSARY EDUCATION SOCIETY)