A trading post in the North Pole where children send letters.

North America's first frozen mummified remains of an ice age steppe bison, the 36,000 year-old mummy named "Blue Babe."

The king of U.S. high points towers over every other peak on the continent.

Cathedral carved out of salt, located a mile below the earth's surface.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.

This Bogotá museum houses the world's largest collection of pre-Columbian gold relics.

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

This stucco building in North Africa was the first American-owned property on foreign soil.

Along the most northwestern point in Africa is an ancient cave surrounded by legends.

New Zealand's only running funicular railway.

A gigantic mechanical bull rages over unsuspecting passengers at Birmingham’s central station.

Climb inside an iron crystal magnified 165 billion times its normal size.

Cities of the world and famous Thai monuments in minature.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

A little sculpture with a large wardrobe.

Come for the flowers, stay for the bats!

The world-record holder for the longest bridge stretching continuously over water.

This elaborate temple was built around one of the Buddha's teeth.

A railway, a waterway, and a roadway all in one, suspended over a rushing river.

A collection of vehicles across American military history.

Catch a ride through the Pennsylvania countryside on this historic narrow-gauge railroad.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

In 1909, the steepest and most difficult piece of track on the Canadian Pacific Railway was replaced with a series of spiralling tunnels cut into the mountains.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.