The defensive tower was built centuries ago to warn locals of Berber pirate attacks.

Engineering ingenuity during the battle of Gibraltar.

Red, white, and blue painted steps along with a Union Jack celebrate the outcome of Gibraltar's 1967 referendum.

Many of the tombs contain victims of yellow fever epidemics.

The history of Reykjavik told through a historical village and live actors.

Where a neoclassical sculptor rests at the heart of the museum devoted to him.

Twisted girders are all that remain of an Icelandic bridge that was wiped out by a combination of volcanic heat and glacial floods.

The first green space constructed on an elevated viaduct.

Iceland's tribute to its thankless civil servants.

Originally commissioned as a sculpture to reflect the history of Belfast's red-light district, the final sculpture has been banned from Belfast public land.

This ex-prison dates back to the Middle Ages.

It’s a painted window that looks completely real, hiding on a building in the market square.

A collection of old neon signs from all over Poland line a secluded courtyard.

Thousands of miniature bronze sculptures have taken over this city square creating a unique art installation.

Charming small streets lined with well preserved wooden houses dating to the 18th and 19th century.

A bold sculpture highlighting the stark inequality between Western affluence and developing world hardship.

This remarkably well-preserved mosque stands amid an 11th-century caravansary.

A geological bull's-eye visible from outer space.

A close look reveals that the Scottish monument is just slightly off-kilter.

Once standing on solid ground, this slender beacon is a victim of the very shoreline it was charged with announcing.

This hidden alley near the location of Rome's first theater was the site of a curious miracle.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

The palace for King Gustav III was never completed, but the foundation remains tucked away in this city park.

This unassuming bridge is most likely one of Michelangelo's unfinished masterworks.