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

This suburban house is made of dirt, and almost sparked a revolution in home construction.

Volcanic stone sentinels stand watch at a Korean Bell Garden in Virginia.

The ruined remains of a coal mining ghost town are hidden within the woods.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

An out-of-place Air Force radar dome is all that denotes this park as a former missile launch site.

A swimming hole in the historic industrial quarry that supplied the marble for the Baltimore Washington Monument.

This stately 19th century library pushed architectural boundaries at a time when the public library movement was just taking off.

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

The largest cemetery for enslaved people in Loudoun County was almost lost to history, if not for the research of a minister.

This abandoned Victorian-style house was built in 1884.

This general store is more than a century old and home to various oddities and antiques.

A monument marks the location of the first successful steamboat demonstration.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

Built by the patriotic residents of Boonsboro in a single day.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

The whole world in one water tank.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

A public art jibe at one of the United States’ oldest and longest-serving senators.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.