Indiana Jones 4 - Crystal Skull

In August of 1949, the Soviet Union successfully tested its first weapon of mass destruction. Dubbed “Joe-1" (after Joseph Stalin), the Russians’ hydrogen bomb took the U.S. government by surprise.

Only four years previously - on the 16th of July, 1945 - the United States had tested the world’s first atomic bomb. Its power shocked even the men who designed it, and Americans were worried that the USSR would develop a bomb of its own. It didn’t take long for their worst fears to be realized.

What happened during that very first test? A plutonium bomb (which scientists nicknamed “the gadget”) was assembled and readied for testing. The detonation site was located 210 miles south of Los Alamos (New Mexico) in an area called Jornada del Muerto (“Journey of Death”).

At first scientists witnessed (this is a BBC video recreation) a fireball.  Sixteen milliseconds later  the fireball grew into a full-blown “mushroom” cloud. Luis W. Alvarez, a scientist who witnessed the blast, drew a picture of the first “mushroom cloud” ever seen.

Twenty-four hours later, scientists and Major General Leslie Groves inspected "Trinity Crater,”  the spot where the bomb went off (otherwise known as “ground zero”).  Temperatures at the test tower had been so high that Robert Oppenheimer (the project’s scientific director) and General Groves (its military leader) saw that the soil now had a kind of glassy crust (called “trinitite”).

The next month atomic bombs were dropped on two Japanese cities, and the world learned what happens when people are near an exploding nuclear weapon. If they aren’t maimed, disfigured or vaporized, they might later die of radiation sickness.