Proto-CIA agents trained with grenades in the sand traps and fired machine guns from the fairways.

The walls of the iconic dome are hollow and have a secret stairway.

Every drop of D.C. tap water flows through this old waterworks.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

Perhaps the most scandalous statue of America's first president.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

Decades before the scandal, this staircase on the river was a literal "water gate."

The national park was once a plantation estate.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

A portal into the bricked up canal that runs through the heart of Washington D.C.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

Before Nixon, "watergate" meant canals.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

A historic ruin just 20 feet away from a busy highway onramp.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.