A unique configuration of blown glass can be found inside this hotel lobby.

A preposterously luxurious hotel with gold-plated iPads, Rolls Royce chauffeurs, and a staff that trains by watching "Downton Abbey."

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

This beautifully restored fortification kept the city safe for centuries.

This bazaar is one of the oldest in the Arabian world.

This spectacular mosque houses the second-largest chandelier in the world.

A statue in the center of Dublin dedicated to one of their favorite sons of rock & roll.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

Europe's official "zero-level," the equator of elevation.

The best bagels in Berlin are tucked away in an independent bookstore.

Super-heavy Nazi architectural experiment.

Bridge that died in war and was resurected.

This picturesque monastery at the base of a cliff is a peaceful oasis open to all visitors.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

On top of a resort town as old as the Bronze Age sits an incredible war memorial statue overlooking the beaches below.

Perhaps the most spectacular grotto along the Algarve coastline.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A whimsical bridge adorned with decorative dragons.

This ossuary is more than five centuries old and is heralded as one of the finest in Switzerland.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

An ancient octagonal weather station named for the eight Greek gods of wind.