For survivors of the atomic bombings of Hiroshima and Nagasaki, the haunting images of those fateful days remain vivid after 75 years.

At 8:15 a.m. on Aug. 6, 1945, some 350,000 people in Hiroshima were just beginning their day when a uranium bomb, nicknamed “Little Boy,” detonated 580 meters above the city, killing an estimated 70,000 people.

Three days later, at 11:02 a.m. on Aug. 9, U.S. forces dropped a plutonium bomb, codenamed “Fat Man,” on Nagasaki, which exploded at 503 meters, killing another 40,000 people.