Seventy-five years ago today, Man entered the Atomic Age. Man did this with the plutonium created in the reactors at the Hanford Engineering Works in Washington State.
In the early morning of July 16, 1945 (About half after 5AM), the experimental implosion device was tested near Alamogordo, New Mexico. It created a HUGE explosion. You can read more about it here and here.
Then, twenty-four years later, man left this planet for a different one. Three men lifted off from Earth and left orbit for the Moon.
All-in-all, this is a historically significant day.