An underground city of salt.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

Modern art meets modern convenience in possibly the world's most architecturally important public bathroom.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

A hidden medieval crypt where a famous legend says the devil used to teach black magic.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

An unusual but excellent display created in the 1930s as propaganda against the Freemasons.

A fascinating and enormous collection of natural history exhibits stained by a dark colonial legacy.

A roadside park in eastern Maine first marked the halfway point between the equator and North Pole with a brass pin in 1896.

This sheep farm has been forever transformed since being built for “The Hobbit” film series.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

An unusual round church in London with a Templar past.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

A nostalgic bibliographic gem.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

Perhaps the most scandalous statue of America's first president.

A section of the long chain that blocked enemy ships from entering Constantinople.