This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Statue of death tucked in the University of Medicine courtyard.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

France's most famous cemetery, with some of its most curious tombs.

An L.A. traffic island where the faces of locals have been carved into massive granite eggs.

The remains of a 12th-century chapter house in Golden Gate Park.

This forgotten Frank Lloyd Wright house is an architectural marvel at the end of a sleepy residential street.

Beautiful Victorian buildings from L.A.'s forgotten architectural past.

Etched into a dry lake bed, this massive directional indicator is accurate without magnets.

Where decommissioned airplanes and helicopters go to become part of Hollywood.

Machinery left over from California's once thriving mercury industry now attracts artists and explorers.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

An artsy hidden staircase leads to breathtaking views of San Francisco.

Settled by the Church of Jesus Christ of Latter-day Saints in 1859, this abandoned frontier town has appeared in several films.

A striking, menacing sandstone peak towering above a landscape that's equal parts Mordor and the Moon.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

A futuristic temple of light uses prisms and rainbows to create an atmosphere of peace.

These aggressively sustainable art homes look like something out of 1970's science fiction.

All that remains of this abandoned coal town is a beautiful, haunting cemetery.