This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

Five candy-colored villages on the Italian Riviera.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

A sharp bend in a dramatic river canyon cut through red rocks.

A bypass decorated with large wooden troll carvings.

Isak Heartstone, a 15-foot wooden troll made out of recycled materials.

An abandoned quicksilver mining town surrounded by the Big Bend parks.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Deep scars on the earth left by the Ice Age.

Take a drunken tour inside the world's largest known geode.

The world's tallest doric column is this Ohio monument to a naval victory in the War of 1812.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

This unique crypt designed by Frank Lloyd Wright for his longtime friend was not completed in either man's lifetime.

The seat of Buffalo government is a gorgeous Art Deco palace.

The absurd creation is a compulsory destination for selfies in Buffalo.

A glimpse of a waterfall is reached by a steel catwalk along a slot canyon located in an Ouray city park.

Home to a 26-foot-tall statue of an American icon.