America's post-nuclear-attack chambers of Congress.

Home of a 28-foot tall stalagmite known as the War Club.

The tallest waterfall in West Virginia.

In West Virginia, you can walk across the longest single-arch bridge in the Western Hemisphere.

This functioning mill was built in the 1970s using parts from several other West Virginia mills.

This memorial pays homage to Pueblo's four Medal of Honor recipients.

A futuristic hovertrain is parked unceremoniously alongside a nondescript road.

These murals from the 1920s beautifully depict America’s industrial age.

Jamestown may have been the first permanent English settlement in the Americas, but the colonists made landfall at a lesser known cape.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

The video game-themed street art first popped up in the French city.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

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

When you're a great Russian Tsar, even your vomit gets a statue.

A bronze statue of the fictional character nicknamed "Mrs. Hat" from a beloved Belgian comedy.

A little sculpture with a large wardrobe.

This cannonball has been lodged in the church wall since a 1695 bombardment destroyed the city center.

A beautiful Victorian statue shows France's enduring love of the rhinoceros.

A fantastical 13th-century fortification sandwiched by a modern hotel in central Brussels.

Unsurprisingly, Holland is home to one of the most magnificent flower gardens in the world.