DECLASSIFIED
The Greatest Secret Ohio Ever Kept
How Dayton built the trigger for the atomic bomb inside a tennis court — and a Soviet spy stole the recipe
In 1943, the U.S. government turned an elegant indoor tennis court in affluent Oakwood, Ohio into a polonium processing plant. The Runnymede Playhouse became the heart of the Dayton Project, a covert operation so secret that its own workers didn't fully understand what they were building. They were building the trigger for the atomic bomb.
The polonium initiators developed in this suburb were used in both Little Boy and Fat Man. A Soviet spy named George Koval penetrated the project and passed secrets to the GRU. The tennis court became so radioactive it had to be dismantled and buried in Tennessee.