Explore the flooded remains of a limestone mine in Kentucky.

Beautiful waterfalls grace a canyon visibly torn by a violent tornado.

Step back in time to explore 19th-century Appalachian life, from blacksmiths to Model Ts.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

The hulking remains of the Leesburg Lime Company Kiln lie dormant behind a historical marker close to the W&OD trail.

This giant 200-year-old ginkgo is one of the largest in the United States.

Exact replica of the ancient monument, but much, much lighter.

A double agent hid information for the Soviet Union beneath this bridge for more than 20 years.

This eye-catching sculpture of rural life seems a bit out of place at a suburban intersection in front of a car dealership.

This local mascot has been a presence in the area since the 1960s.

The former home of Dr. E.B. Henderson, also known as the "Father of Black Basketball."

This monument traces the segregation line that inspired the first rural branch of the NAACP.

This "castle" is actually a limestone and quartz formation hidden along a trail.

A whopping 14,000 copper coins cover this miniature fighter jet.

The site of the climactic scene from the classic horror film is now a historic landmark.

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

Garments from across the globe call this hidden gem home.

The national park was once a plantation estate.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

The romance of early commercial flight still fills this Art Deco destination.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.