Washington's Tomb (United States Capitol)

Washington's Tomb is an empty burial chamber two stories directly below the rotunda of the United States Capitol building in Washington, D.C. It was included in the original design of the building by William Thornton and intended to entomb the body of George Washington, the first president of the United States. The original design of the rotunda, and the Crypt beneath it, included a central glass floor allowing the public to view Washington's Tomb two floors below, but this was never implemented.

Source: Wikipedia — Washington's Tomb (United States Capitol) (CC BY-SA 4.0)