A series of mysterious metal artwork adorn this harbor walkway.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

A mythological Celtic beast built with thousands of colorful tiles stands guard over a historic canal junction.

A book bound in the skin of an infamous criminal, along with countless other specimens.

This tiny little cave was said to have been a refuge for a saint with a glowing arm.

This grand hydraulic installation has provided water for townspeople since the Middle Ages.

Founded in 670, this ancient mosque is an architectural time portal.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

The ancient heart of Tunis is an enormous maze of narrow streets and alleyways.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

These upturned herring boats make nifty storage sheds for fishing goods.

This tidal island, a sacred site in early English Christianity, was the target of a notable Viking invasion.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

The sign at the garden gate reads: “These Plants Can Kill.”

This giant wooden treehouse within a sprawling garden has its own eatery.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

An eccentric aristocrat brought these Australian natives to their current Scottish home.

The half-finished remains of what would have been Scotland’s biggest piece of landscape art.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

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

In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.