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.

Why a column on the entrance is inscribed with a verse from the Quran is one of Sicily's many mysteries.

Deceased nuns were placed on stone chairs to decompose, while the surviving nuns prayed near the lifeless bodies.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.

This one-of-a-kind archeological site is home to strange prehistoric ruins, the original use of which is still a mystery.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

A petite white lighthouse perched on the ancient core of Stromboli Volcano.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.

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

Ancient snack bar of the Roman Empire re-opened.

Italian cave with exceptional acoustics and an unsavory history.

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

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

2300-year-old Roman road connecting the empire.

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

The yawning maw of this pagan visage is said to bite off the hands of liars.

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

In the heart of Medellín, an artsy urban complex sets the stage for demonstrations and protests.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

Amsterdam's former hotspot for public executions and dissections.

A public urinal so pretty, it was declared a national monument.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.