Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.

A beautiful but toxic fountain of mercury.

A stately palace has been converted into the world's largest cannabis museum.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

This semi-secret storybook hedge maze is also the oldest garden in the city.

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.

Artist's eccentric property excessively decorated with found objects and work of his own.

This massive blockhead sculpture hides an entire library.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

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

A huge wooden clock that is so beautiful its creator was forcibly blinded.

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

The oldest private art gallery in all of Hungary.

A Hungarian optometrist's charming collection of Asian art and curiosities.

A two-way chairlift system between Zugliget and the highest point in the city.

Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

Electrical curiosity museum housed in an old transformer station.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

A fake Transylvanian castle houses a cathedral of antlers.

This hidden art nouveau gem was designed by an architect in search of a national style.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.