An existential riddle in the world's largest ancient castle.

One of Belgrade's most beloved animals.

An open-air museum dedicated to tombstones and roadside stone monuments.

This spa park features an open-air museum of abstract marble sculptures.

Backwards hour and minute hands and a timing mechanism that fluctuates with the temperature led to this clock tower's local nickname.

This art installation pays homage to the famed stones of European lore.

The unusual sculptures are believed to be powerful political symbols.

Near Belgrade, an ancient-looking sarcophagus serves as a World War I monument.

The interior of this Serbian royal family's mausoleum is covered with exquisite mosaics.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Dine amidst exotic plants at this former royal greenhouse.

The Habsburgs' royal collections of art and wonders.

100 year tradition of fist fights, marked by marble footsteps.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

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.

Macabre astrological automaton clock dating to the late 1400s.

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

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

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A mocking tribute to the past and modern leadership of Prague.

Museum celebrating the ocean, with the largest wunderkammer dedicated to sea exploration.