These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."

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

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

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

This steep cable railway has been hoisting passengers in the heart of Québec City for over a century.

A contemporary fresco movement illustrates the region's rich history.

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The highest point in Maryland is only accessible by hiking through another state.

Pennsylvania's highest point is spotted with boulders which were pushed to the surface by nothing but cold.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

This one-room cabin where the young colonel slept during the French and Indian War.

A subterranean house of worship carved right out of the bedrock.

A little sculpture with a large wardrobe.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

A favorite with sightseers, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

St George's Leprosy Museum depicts the gruesome afflictions of those suffering from the disease.

The burning of this 12th-century church kicked off a campaign of Norwegian Black Metal terror.

It houses the remains of a 17th-century version of the Titanic.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

The whole world in one water tank.

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.