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

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Ancient snack bar of the Roman Empire re-opened.

Erotic art covers the walls of the largest ancient pleasure palace.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

Pilgrimage site for star-crossed lovers.

Go inside to really appreciate this 500-year-old technological masterpiece.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Pompeii's less famous neighbor is still revealing her secrets.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

This quaint Hungarian railway system is operated exclusively by children between the ages of 10 and 14.

Budapest's Communist-era statues, banished to the suburbs.

Museum dedicated to the terror regimes of Hungary.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The telescope that discovered Neptune.

An abandoned train station in Munich constructed for the 1972 Olympic games.

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