There's a crumbling old mansion inside the Smithsonian National Zoo.

A cablecar-station-turned-revolving restaurant with 360-degree views of the Swiss skyline.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A local student's chance encounter with Keith Haring led to the creation of one of Europe's largest murals.

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.

Breathtaking and huge 430 year old maps of Italy.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

The adorable animals return to this nature reserve every fall to give birth to their pups.

Despite its ornamental looks, this towering Tuscan-inspired anomaly was a masterpiece in hydraulic engineering.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

One of the first monuments dedicated to the accomplishments of the great Vice Admiral, Horatio Nelson.

A six-ton wedding present for the King of the Scots.

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

A dilapidated dock tells the story of Titanic's missed arrival.