This unique architectural wonder is home to luxury apartments.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

A stunning medieval castle owned and restored by the famed actor Jeremy Irons.

This Scottish burial tomb once held hundreds of ancient eagle bones.

This tin chapel was built by POW's during World War II and is painted to look like something much more grand.

The discovery of this Neolithic settlement, which contained a Stone Age "cathedral," threw archaeologists for a loop.

Enter the world under the hill at this ancient UK burial chamber.

The world's largest model of our planetary system.

The largest salt lake in the Sahara is mysteriously alluring.

Made famous by "Star Wars," these troglodyte homes face an uncertain future.

On Gellért Hill, this statue depicts the tragic tale of lovers divided by the Danube.

Ancient serpentine sacrifice holder that has stood the test of time.

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

1513 Turkish world map, full of European state secrets and snarky commentary.

Turkish adventurer antiques in the heart of the Grand Bazaar.

A marvel of Byzantine engineering under the streets of Istanbul.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

A bridge that has seen many reiterations over its lifetime.

A condensed piece of China floating in a Dutch harbor.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.

A statue of the second-tallest Dutchman in history.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.