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

An ancient church on a tiny island covered in stone bible stories has controversially been turned into a museum.

A Lycian city of the dead carved into the hillside of Southern Turkey, complete with startlingly human touches.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This historic pub has maintained much of its 1906 decor, including a small sequestered room for women, where orders were slipped through a tiny window.

A statue honors the children who fought Nazis in Poland.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

An underground city of salt.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

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

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

Colorful and chaotic stacked hotel in North Holland.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

A floating cat sanctuary on an Amsterdam canal.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

The world's only museum devoted to the wonders of fluorescence.

It took over half a century but a Russian monument to a famous and tragic space pup finally stands in Moscow.

Museum celebrating the achievements of the Soviet space program.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.