The gravestones in this historic cemetery are carved with mysterious faces.

In this truly magical place, rent hasn't been raised since the year 1520.

On the Irish coast, 18 members of the Howard family are eternally resting in an Egyptian pyramid.

A seven-story 1920s mausoleum outside Denver houses thousands of remains.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

The Neolithic megalith was one of the first archaeological ruins protected by the British government.

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

Everything you always wanted to know about borates is here.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

The front yard of an Upper East Side town house hides the last fragment of one of New York's most famous theatres.

This lavish room at NYC's French Embassy is a rare relic from the end of the Gilded Age.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

A subterranean world of tunnels links several buildings of this rare 19th-century asylum.

Join in a Seance at the Swedenborgian Church.

Most-visited and most-photographed slot canyon in the American Southwest.

Curious cave that stays a cool 56 degrees all year long.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The rocks in this arid basin leave trails of movement behind them.

Ice roads, deep holes and 3,500 pounds of diamonds.

Handcrafted thermal spa washes away each night with the tide.

Made of bronze and wearing a blue gown, this lady sat in the same location in the Yantic Cemetery for more than 119 years.

The Connecticut village named for its subterranean thunder.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.