This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Secret refuge and museum of the Duke of Florence.

Five candy-colored villages on the Italian Riviera.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

The first botanical garden, a feather in the cap of the Grand Duke of Tuscany.

A local student's chance encounter with Keith Haring led to the creation of one of Europe's largest murals.

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

Copenhagen's celebrated theme park and gardens.

Visitors are treated to a stained glass kaleidoscope interior inside this work of art.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

The lost American era of gunfighters, bandits, Indians and steam trains is recreated in Sweden.

A devilish mask still mocks a king’s rumored love nest across the street.

This castle ruin in the middle of nowhere is a gem for wildlife enthusiasts.

A steel paper plane is all that remains of a crashed aircraft that caused an amazingly small amount of damage.

This gem from the industrial age helps visitors and residents alike traverse hilly Stockholm.

When this 18th-century observatory's meridian was moved, it set Sweden's time back by 0.04 seconds.

The library's graceful rotunda is like a bibliophile's temple.

Small Easter eggs are hidden in the ventilation holes of the city's newest trains.

This pair of unsuspecting buildings are in fact the very first modern skyscrapers in Europe.

A golden plaque marks the site of the mysterious unsolved assassination of the former Swedish prime minister.

A concrete mushroom that divided Stockholm residents for nearly a century.

Sweden's "good old days" painstakingly re-created in a model village.

It houses the remains of a 17th-century version of the Titanic.

The Swedish flag over this small naval fort signals that the nation is at peace.