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

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.

Unannounced visitors are now welcome at the site of the largest Prohibition-era bootlegging operation in the region.

One of the oldest active carousels in the country—but it might be missed by all but the keenest-eyed boardwalk strollers.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

This historic lighthouse was well known for the large number of women who served as its keeper.

Explore the legends surrounding these mythical sea creatures inside this museum.

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

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

Before Nixon, "watergate" meant canals.

In the basement of the U.S. Capitol Building is a hidden storage room full of ornate floor tiles leftover from the 1850s.

Largest Roman Catholic church in North America.

The most decorated dog of World War I is preserved in the Smithsonian.

An Industrial Revolution-era public work that purified water using nothing but sand.

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Meet some of the most prominent figures in Black history through life-sized wax models.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

Faces carved into the cliffs create an otherworldly walking trail.

This abandoned bridge to nowhere stands secluded in the woods of a Cleveland suburb.

Prison made famous by The Shawshank Redemption has been out of commission since 1990.

A castle built by an eccentric medieval enthusiast in rural Ohio.

Rare recess caves fill this unbelievably beautiful Ohio park.