An underground city of salt.

One of the world's few mounted blue whales, its jaws are hinged open allowing visitors to descend into a lounge.

A Gothic-inspired fish market is Gothenburg's best place to find loaves and fishes.

The world's biggest floating museum in Gothenburg, Sweden.

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

This colorful but controversial ceiling has been likened to a 21st-century Sistine Chapel.

The world's largest second-hand graces a clock surrounded by constantly changing flower beds. 

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

Lyon's "Wall of the Silk Weavers" is one of the largest murals in Europe.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Hundreds of hidden passageways weave through the old quarters of Lyon.

Monsters and miniatures are held in equal esteem at this wondrous museum.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Lyon's miniature version of the Eiffel Tower was built as a statement in support of French secularism.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

The first modern cemetery of Lyon is complete with more than 200 chapels and monuments.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Eighty million natural history specimens call this gargantuan museum home.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

In France, a medieval-style home pays homage to an intrepid explorer who discovered Québec.

On this romantic tidal island reachable only at low tide the tomb of a famous French writer overlooks the sea.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.