A celebrity from the late Cretaceous period.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

This church built atop a gas station promises to "equip you for the next stage in your life’s journey."

Island where motor vehicles are banned -- home to the only carless highway in the United States.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

This bridge was constructed from the rubble of the infamous Bastille.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This ancient theater was once the home of fierce gladiatorial battles.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

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

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

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 house where John Wilkes Booth conspired with his co-conspirators.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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