A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Inside this Krakow church, an explosion of psychedelic color.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

In the summer, the area around this sculpture transforms into a vibrant concert venue.

Special benches that play Chopin's music are scattered throughout his native city.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

Op-art architecture designed for happiness.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

The exact whereabouts of this surreal cabinet of curiosities are rarely the same place twice.

Located inside Hoge Veluwe National Park, this museum began as the private collection of a prominent female art collector.

66,000 pieces of art, donated by one of the world's richest men.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

A tiny graveyard with a mysterious past.

You'll find rocket launchers, not rollercoasters, at Russia's “military Disneyland.”

Orthodox church partially financed by Tsar Nicolas II.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

This cheerfully-named branch of the Chicago River is the fetid result of years of blood, entrails, and meatpacking waste.

These abandoned grain silos and tunnels are an urban exploration dream.

The world's tallest carillon is located at the top of this skyscraper in Mexico City.

A colorful "forest" made entirely from three tons of recycled plastic waste.

This art shopping center still boasts pieces of its past as a textile factory.