Unchanged for centuries, this medieval library keeps its books in chains.

Bell tower juts out from a village buried under a lake.

The mysterious megaliths have enchanted and intrigued visitors for thousands of years.

A red-brick beacon stands against the tempestuous Atlantic, on the windiest site in the United Kingdom.

Dedicated to the history of the 1,000 nuclear missiles that once covered the Great Plains.

Hang with reindeer at this 400-year-old Sámi market.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

This impressive chasm is one of the longest natural underground cavities in the world.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.

A close look reveals that the Scottish monument is just slightly off-kilter.

Towering sandstone rock formations where 'The Chronicles of Narnia' was filmed.

Europe's largest natural bridge has a 19th century royal chateau built into its side.

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

A medieval village, with red wooden cottages around a stone church, stands as a well-preserved example of a settlement type that was once common in northern Sweden.

This little gallery is devoted to one small town's passion for a very special cheese.

An abandoned lighthouse awaits its destiny: being buried under shifting sand.

A set of outdoor stairs named in honor of a famous Austrian artist.

The first modernist church in Europe.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Op-art architecture designed for happiness.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.