Oak Ridge was Tennessee's fifth-largest city during World War II, but it was also America's biggest secret.
Behind walls, inside behemoth buildings, scientists toiled away developing a nuclear weapon that would end the war and change international relations forever. Oak Ridge was established in 1942 by the federal government specifically as a production site for the Manhattan Project, the top-secret name of the World War II atomic bomb project.
Today, Oak Ridge is still a community centered on nuclear energy and high-tech studies, but most of the Cold War-era secrets are completely out of the bag. City leaders now use Oak Ridge's links to the bomb as a draw for tourists.
"Many people don't know that Oak Ridge was the headquarters for the Manhattan Project," said Niki Reynolds, spokeswoman for the Oak Ridge Convention and Visitors Bureau. "But of all the Manhattan sites, we still have the most history for people to see."
At its production peak, 70,000 people worked at Oak Ridge, but just a handful knew that they were actually helping to make the bombs that eventually would be dropped on the Japanese cities of Hiroshima and Nagasaki.
Nearly 70 years after its creation, Oak Ridge still processes uranium at three of the four major facilities created for wartime bomb production -- the K-25, Y-12 and X-10 plants.
Oak Ridge also is home to the largest U.S. Department of Energy laboratory, which is managed by UT-Battelle and employs more than 4,800 workers in a variety of energy, materials and nanoscience research initiatives. The Oak Ridge National Laboratory houses two of the most advanced neutron scattering research facilities in the world, the Spallation Neutron Source and the High Flux Isotope Reactor.
The city hosts the annual Secret City Festival on the third Friday and Saturday in June. Summer also is when many of the still-functioning Cold War buildings are open to the public.
Year round, the American Museum of Science and Energy displays many photos and artifacts.
Oak Ridge isn't all about history and nuclear energy. It also has world-class rowing facilities at Melton Hill Lake. The city is also home to the Children's Museum of Oak Ridge.
At a glance
-- Population: 27,571.
-- Best things to do: American Museum of Science and Energy, which tells the story of the development of Oak Ridge. It also displays model weapons. Entrance fees are $5 for adults, $3 for children.
-- Biggest employers: U.S. Department of Energy, federal government.
-- Miles from downtown Chattanooga: 109.
-- Geographic features: Melton Hill Lake, a 5,000-acre lake with 193 miles of shoreline.
-- Date founded: 1942.
-- Historic info: Founded by the federal government during World War II to develop a secret nuclear weapons program.
-- Most-famous residents: Elaine Hendrix, actress, starred in "The Parent Trap;" Mitch Rouse, writer, director and actor; Megan Fox, actress, "Transformers," born in Oak Ridge, lived in Kingsport.
-- Unique traditions: Secret City Festival celebrates Oak Ridge's formerly secret involvement in nuclear energy development.
-- Best-kept secret: The Children's Museum of Oak Ridge, $7 admission.