" In the hills of Tennessee, monumental plants were being built to separate the rare isotope U-235 from U-238 using two different methods. Beside the Columbia River in Washington State, construction had commenced on reactors that used two hundred tons of uranium moderated by twelve hundred tons of graphite. Working with their Canadian ally, the Americans were building a massive heavy water plant at a hydropower station in Trail, British Columbia. At the Los Alamos Ranch School in New Mexico, a small city of physicists was working to build a functioning fission bomb. "

― Neal Bascomb , The Winter Fortress: The Epic Mission to Sabotage Hitler’s Atomic Bomb