Where scientists keep miles of very valuable ice from Antarctica and Greenland from melting.

Amsterdam's former hotspot for public executions and dissections.

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.

A floating cat sanctuary on an Amsterdam canal.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

The mysterious "Candelabra of the Andes" could represent anything from a god's trident to a hallucinogenic plant.

Mystic Incan rock piles three miles above sea level.

The highway's southernmost spot is a beloved local attraction.

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

Breathtaking and huge 430 year old maps of Italy.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

This abandoned psychiatric hospital once housed more than 4,000 patients in the middle of a quaint New England town.

The cave where two British judges hid in exile after sentencing the king to death.

Panoramic views of the city of New Haven and the Long Island Sound, with a side of history.

A lone tower rises above the cliffs in a city park, offering fantastic views of the Connecticut landscape.

A reliquary of pop culture marvels, including the world's largest (and most terrifying) Jack-in-the-Box.

With some 500,000 books across five buildings, this bookstore is a reader's paradise.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

A monument celebrating the idea of reaching inaccessible places.

Berlin's old airport.

A fascinating insight into daily life in the Eastern Bloc.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.