"Holy Wisdom" overlooks the city that became its namesake.

A vast Communist-era exhibition space in the Bulgarian capital.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

A striking symbol of the Bulgarian capital.

Sofia's legislative center is continuously reinventing itself.

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.

Where the lovelorn find a home for their sentimental keepsakes.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

A countryside Romanian cemetery filled with colorful crosses bearing lyrical, ironic, or satirical rhymes.

Romania's triumphal arch looks out over Bucharest.

This massive underground salt mine now holds a sci-fi theme park in its depths.

A stunning 18th century pharmacy and medieval chemist's collection.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

The world's most active stratovolcano is almost always erupting.

Italian cave with exceptional acoustics and an unsavory history.

142 ceramic steps become a mosaic once a year.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

Dynastic Home of the De Piro Family.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

The last of its kind in the country.

Once strictly off-limits, this lower level housing curious and priceless vehicles of the Petersen Automotive Museum is now open to the public.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

These spartan apartments are provided to clergymen visiting Vatican City.