K-25

K-25 was a significant facility in the history of the Manhattan Project, which was the United States' World War II effort to develop atomic weapons. Located in Oak Ridge, Tennessee, K-25 was a large factory built for the purpose of uranium enrichment, specifically using the gaseous diffusion process. Constructed in the early 1940s, K-25 was one of the largest buildings in the world at the time, covering over 1 million square feet.