This beautifully designed star-shaped fort was the premier defense system of the late 1500s.

The nerve center of a massive, state-of-the art radio telescope that sprawls across Western Europe.

The 20-mile causeway that separates the Netherlands from the sea.

This giant radio telescope would be a rusting ruin if it hadn't become such a beloved relic.

Building Men of War and Indiamen from Holland's Golden Age.

This giant wire frame man sculpture is crouched in contemplation.

This steel frame is a skeletal mirage of a lost 16th-century stone building.

This unique bridge physically lifts a piece of the road into the air to let boats pass by.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

This arch granting triumphal entrance into Antalya was designed to honor the emperor's visit.

Once described as the "Eagle's Nest," this ruined ancient city rests on a remote mountaintop.

The best-preserved ancient theater in the world.

This museum dedicated to the famous comedy duo is located in the town where Stan Laurel was born.

This rare aquatic phenomenon is one of the more accessible tidal bores in Morecambe Bay.

A 30-acre garden inspired by the principles of modern physics.

One of the best-preserved, yet least visited stone circle sites in Cumbria.

What was once England's second-richest abbey is now a haunting ruin.

It's believed a local adventurer spent 50 years living inside this cave.

Stonehenge has nothing on Castlerigg’s views.

An impressive Neolithic henge with banks nearly 10 feet high.

For decades, a bottle factory dumped their waste into these waters—now it's considered the best sea glass beach in England.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

Cave on extinct volcano, once home to famous mathematician Pythagoras.

This famous city eluded concrete detection until the early 2000's.