Excerpt from History.com: A specially adapted B-29 bomber, called "Bock's Car," after its usual commander, Frederick Bock, took off from Tinian Island under the command of Maj. Charles W. Sweeney. Nagasaki was a shipbuilding center, the very industry intended for destruction. The bomb was dropped at 11:02 a.m., 1,650 feet above the city. The explosion unleashed the equivalent force of 22,000 tons of TNT. The hills that surrounded the city did a better job of containing the destructive force, but the number killed is estimated at anywhere between 60,000 and 80,000 (exact figures are impossible, the blast having obliterated bodies and disintegrated records).