The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

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

Copenhagen's celebrated theme park and gardens.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

This chimerical bridge/tunnel appears to dead end right into the sea.

A rare surviving Victorian greenhouse designed specifically to house giant water lilies.

The preserved arm of a third-century sorcerer is believed to have the power to lift curses and spells.

What looks like a birch tree smushed between two pieces of glass often confounds commuters.

A rare example of this century-old British tank stands near the center of town in Ashford.

The ancient mosaics here are considered among the finest in the world, and serve as a stunning record of Greco-Roman daily life.

Once part of an ancient international harbor, it's now an all-you-can-eat shrimp buffet for flamingos and other water birds.

The water here is so clear you can see the mysteriously sunken ship from the surface.

Romania's triumphal arch looks out over Bucharest.

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

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

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

Sweden's "good old days" painstakingly re-created in a model village.

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

This roundabout was renamed in honor of the Swedish king's royal fender-bender.

For a couple of months each year this Swedish city turns into a festive neon phantasmagoria.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.