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

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Legend has it this spring formed at the spot where a medieval Swedish king was killed.

A large collection of ancient runestones decorates this university courtyard.

A prehistoric geological oddity tucked behind Stockholm's natural history museum.

The Swedish flag over this small naval fort signals that the nation is at peace.

Stockholm's narrowest alley is barely over two feet wide.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Stockholm's deepest subway station is also a stunning ecological wonder.

It houses the remains of a 17th-century version of the Titanic.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

Northern Ireland's Brobdingnagian stepping stones.

The atmospheric road was never meant to be so creepy.

Come for the oysters, stay for the priceless art honoring inventors across history and Scotland's favorite outdoor sports.

One of the oldest wine cellars in Germany is now a restaurant beneath Bremen's town hall.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

The remains of an ancient Roman city are hidden underneath Bologna's beautiful public library.

A striking memorial recalls thousands of Bolognese men and women killed fighting fascists in World War II.

Time has been frozen at this station since the bombing in 1980—or so it was believed.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.