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

Bizarre Cavern.

A Civil War Museum with some notable medical antiques.

Fascinating museum dedicated to the under-appreciated medical history of urology features some wince-inducing devices.

A Maryland museum dedicated to Black history, housed in a historic church.

This abandoned Victorian-style house was built in 1884.

Electronic inventions that resulted in products and systems we use every day are on display in this labor-of-love museum.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

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

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

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

Tiny observatory made big contributions to the study of the Earth's motion.

One of the oldest train stations still standing in Virginia played a vital role during the Civil War.

Located at the former Lorton Prison the Lucy Burns Museum tells the story of the 91 year history of the prison including the dark chapter of its involvement in the women's suffrage movement.

This golfball sized platinum iridium cylinder is the official starting point for all national weight calibrations

The U.S. government built the million-pound stack of steel during the Space Race.

A state park that once served as an important river crossing, and now offers protected lands for endangered plants and animals.

The last of nine massive kilns that produced many of the red bricks for buildings in Washington, D.C. and northern Virginia in the early 20th century.

Standing for over 200 years, the abandoned home of a Revolutionary War hero and later a succession of prison superintendents.

A remote horde of architectural treasures fit for Indiana Jones.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

The shelves in the back of this thrift store are devoted to saving, not selling, retro tech.

Walk a trail through a historic Quaker town that outlawed slavery in 1777 and was a major waypoint on the Underground Railroad.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.