The Secret City that Helped the U.S. Build the Bomb

"The city, now called Oak Ridge, was once home to 75,000 people, yet it did not appear on any map. Visitors could only get into the town through gated entrances. The vast majority of residents were unwitting participants in the drive to harvest enriched uranium for the "Little Boy" bomb that devastated Hiroshima on August 6, 1945. They only learned exactly what they were doing when they read the big black headlines that proclaimed the war's end.

Nearly 66 years later, Oak Ridge is getting ready to celebrate its heritage--and to party a little, too."

Now home to 29,000 people, the Tennessee city is replete with museums documenting its cloaked past.