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

The tombstone of an unfortunate explorer who disappeared in the Paris Catacombs.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

Notorious artist squat renovated into legal studios.

This small, ingenious cannon once helped regulate Parisian life.

One of London's lost rivers runs through a pipe over the tracks of this subway station.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.

A hands-off space for graffiti artists to hone and display their skills.

This unassuming building produced some of the world's most famous bells.

Black cat statues guard this temple-like Egyptian revival factory.

This South London cemetery holds the remains of more than 15,000 people.

This ancient Egyptian obelisk still bears the wounds of World War I.

Children's hospital in London that operates on royalties received from Peter Pan, which J.M. Barrie signed over in 1929.

The Tudor-style cottage in the middle of the square is not quite what it seems.

This giant disembodied horse head seems to balance impossibly on its nose.

The Cadillac Ranch for monster truck aficionados.

The lecture hall where Alexander Graham Bell first demonstrated the long-distance phone call.

This home is steeped in history from, George Washington to George Corwin, High Sheriff during the Salem Witch Trials.

Statue in Salem of the woman who starred as the witch Samantha in the sitcom "Bewitched."

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

An idyllic swimming pool tells the tale of Hemingway's trouble with women.

The highway's southernmost spot is a beloved local attraction.

A monument celebrating the idea of reaching inaccessible places.