Executions were once held near this beautiful 18th-century fountain.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

This massive library holds what was once the largest book collection in the world.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.

One of the most easily accessible examples of the rare 1960s UFO houses.

The prototype for all Nazi concentration camps.

This magnificent museum claims to house the cranium of a disciple and the skull of a pope.

This abandoned mining village was predicted to resist decay longer than any other modern human settlement.

Legend has it the lovelorn tears of a princess and a shepherd boy formed the blue and green twin lakes in the Azores archipelago.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

A collection of more than 12,000 shoes, displayed in a building shaped like a shoebox.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

The massive machine creates cracking displays of indoor lightning.

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

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

This Costa Rican topiary park is a surreal garden of unearthly delights.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

The same water that fills a luxury resort’s pools feeds these free hot springs in the rainforest.

In Costa Rica's cloud forest, the roots of a woody ficus create a botanical bridge.

This wildlife refuge is home to more than 200 species of birds, as well as monkeys, lizards, and other wildlife.