This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Turntable anonymously received orphans, alms, and groceries.

A bizarre house filled with an astounding array of collections.

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

A skeletal collection of former nautical mainstays.

A spoke-tacular artwork constructed from recycled bicycle rims.

Home to a full cast of the largest woolly mammoth ever recovered in North America. 

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

The ruins of this Alaska gold mine form a gorgeous ghost town.

This whimsical stacked cabin looks like something out of a children's book.

Upside-down trees serve as natural flower pots in this hanging garden of Alaska.