Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

At almost 1,000 years old, this is the oldest known door in all of Britain.

The medieval woodcut-style artwork chronicles life in medieval London.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.

The commemorative stone column conceals a secret laboratory.

A measuring mishap led to these artificial stone ladies losing their stomachs.

An architectural oddity hides in plain sight on this iconic London bridge.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Built by a king and rebuilt by an emperor, this aqueduct transported water for 1,200 years to this ancient Mediterranean hub.

Hidden beneath a washing machine in a fake kibbutz, this secret bullet factory has been preserved as a museum.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Elevated freight railway turned wildly successful urban park.

A terrific purveyor of natural history objects and curios.