The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

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

This 1830s store is believed to be the site of Harriet Tubman's first stand.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

The Forest Service's surprisingly sophisticated collection of wildfire prevention art features America's most beloved bear.

One of the oldest anatomical theaters in the U.S. still in use was once the site of an infamous cadaver riot.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

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

Two dozen pinball games hidden away inside a most unlikely location.

A Civil War Museum with some notable medical antiques.

An abandoned church gets a second life as a massive beer hall and event space.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

This simple convenience store sits on the location where the Ouija board was named—and has a plaque to prove it.

A faded sign from the 1920s remembers Baltimore's resistance toward banning alcohol.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

Ship skeletons haunt Baltimore's waterways.

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

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

An eerie, decaying ghost town destined to fade into the forest.

Fiji mermaids, mummified remains, and recreated cryptids are among the morbid oddities at this Maryland museum.