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

Notorious artist squat renovated into legal studios.

Dine amidst exotic plants at this former royal greenhouse.

The solemn exterior conceals an opulent interior of this 17th century church.

The topiary maze at the Habsburg hunting lodge.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

A spherical "micro-nation" in the heart of Vienna.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

The beautiful baroque library of the Hapsburg empire.

Home to the "Rat King" of Nantes and other wonders of the natural world.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

A tongue-in-cheek arcade where the games are based on everyday life.

A kaleidoscopic warehouse-maze of handmade neon signs.

A historic house left in "dramatic still life."

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Tens of thousands of rocks make up what is thought to be a giant star calendar.

Gladiators battle and chariots race daily in the ruins of a once-great Roman city.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

The palace of the King of Kings, burned by Alexander the Great.

This hunter-gatherer architecture is believed to be the oldest religious complex known.