On July 16, 1945, US Army detonated the first nuclear weapon in New Mexico's Jornada del Muerto desert. Codenamed Trinity, the test was part of the Manhattan Project. Three weeks later, the United States dropped atomic bombs on Hiroshima and Nagasaki. From the Atom Central page about Trinity:
The bomb was detonated, producing an intense flash and a fireball that expanded to 600 meters in two seconds. The explosive power was equivalent to 18.6 kilotons of TNT. It grew to a height of more than 12 kilometers, boiling up in the shape of a mushroom. Forty seconds later, the blast of air from the bomb reached the observation bunkers, along with a long and deafening roar of sound.
About this footage:
Original Trinity Footage restoration includes removing dirt and scratches and minimizing some defects in the processing of the original negative. Three shots include a wide shot, a medium shot and a close up.