This amazing pedestrian suspension bridge in the Swiss Alps would give Indiana Jones nightmares.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

Lavish royal estate punctuated with heated greenhouses.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Large Hadron Collider and the Birthplace of World Wide Web.

German and American troops joined forces to defend this fortress during the strangest battle of World War II.

A pyramid in Central Europe of unknown origin.

A rooftop restaurant hides in plain sight atop Vienna's Palace of Justice.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

This skeleton-filled altar piece served as a backdrop to one of the most iconic scenes in "The Sound of Music."

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

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

Legends surround an ancient tree trunk riddled with nails for good luck.

The Habsburgs' royal collections of art and wonders.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Artfully arranged bones of 5,800 Austrians.

Each year melting snow turns these Austrian hiking trails into scuba zones.

Located right outside of Vienna, visitors can take in expansive views of an ethereal forest.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

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