This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

An eponymous directional signpost erected by the first president of the United States.

These unusual rooms on wheels are holdovers from the 1960s.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.

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

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

The Kirkland Monument remembers a selfless Civil War hero who braved the battlefield to give water to his dying enemies.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

A former major munitions plant that has been converted into a sprawling art space.

This pun was simply waiting to come to life, and one defense contractor made it so.

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.

The rogue roots are gradually consuming some of the historic marble grave markers.

At 207 feet, one of the world's longest continuous escalators.

The narrowest house in America is seven feet of pure spite.

The resting place of a Civil War celebrity's amputated limb.

Outsider art meets paleontology at this roadside reptile repository.

Walk in the footsteps of the famed astronaut at Purdue University.

Purdue students would lean over this iron fence to skirt campus rules against smoking and courting.

This memorial to the Mercury Seven astronaut stands at the site of his former elementary school.

Tombstones carved to look like tree trunks are used for multiple generations of family members.

An unknown number of cholera victims are buried in two nondescript graves.

The massive, original Colgate Clock is mounted on a defunct factory building that was once a prison.