Plaques on its facade commemorate the Tiber's most destructive deluges.

The place where World War I began.

The first mosque in the world to receive electricity.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

A war-torn Olympic relic is being overtaken by graffiti and nature.

Bridge that died in war and was resurected.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

These "bridges" help confused bats cross the road.

Now nearly dry, this lake is said to be the ancient home of the Lady of the Lake, and was once thought to be bottomless.

Follow the original medieval paths that wind through this intriguing section of the city.

The little-known second castle that William the Conqueror built in York.

One of the shortest streets in York has an especially odd name.

This network of narrow, medieval passages has the most delightful name.

A century-old tradition has culminated in a small but singular collection of feline effigies.

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

Hanging within this medieval church are the bones of a beast allegedly slain by a fourth-century saint.

The pile of books behind the dignified writer gave the statue a most undignified nickname.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

Stare out over the lagoon and beyond from this 10th-century campanile on the island where the city of Venice began.

Where Venice's gondolas go for a tune-up.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

The small peaceful island off the Venice tourist circuit is where the city began more than 1,500 years ago.