An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

This poignant sculpture of a gnarled weapon is a symbol of non-violence.

Frequent fliers welcome in this airplane hotel.

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

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

Statue of death tucked in the University of Medicine courtyard.

The tomb of history's greatest potato promoter is surrounded by tubers.

The video game-themed street art first popped up in the French city.

This demon atop the Notre-Dame de Paris looks utterly bored.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

The trials and tribulations of marking Poe's grave.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

How did a French journalist’s grave become the sexiest statue in the cemetery?

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

The oldest of Venice's plague quarantine stations, designed to keep the medieval city safe from disease.

Ancient ruins hidden underneath a modern luxury hotel.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

The astonishing collection of an infamous criminologist.

Secret refuge and museum of the Duke of Florence.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.