The solitary grave of a schooner captain killed by lightning while serving biscuits.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Outdoor exhibits explore the contributions of European, African, and indigenous peoples to American frontier culture.

The celebrated eyesore created by starry-eyed sweethearts.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

Op-art architecture designed for happiness.

From a distance, Latin America's first Baha'i Temple looks like an enormous egg perched atop a hill.

A mysterious dark-skinned Christ statue has been this town's religious center for centuries.

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

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

The Pentagon is so large that it was planned like a city, complete with internal highway infrastructure.

Please don’t anchor your boat onto the Department of Defense’s underwater data cables.

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

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

This unique historical monument features large concrete spheres designed to resemble fallen stars.

One of the last active volcanoes on the Eastern seaboard.

Downtown Minneapolis mixed art and function by turning some of their sewer covers into works of art.

A toweringly silly piece of modern art has been delighting locals since the 1980s.

A store full of vintage and indie toys designed to bring out the kid in even the crustiest of adults.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Once forgotten and built over, this historic Black cemetery now houses a poignant memorial.

Paths are maintained, but trees have taken over plots.