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

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

The studio built by fascists in the hopes of "reviving the film industry" with the occasional propaganda film opportunity thrown in.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

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

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

Jesus' footprints and the first catacombs in the world.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The final resting place of the poets Shelley and Keats.

2300-year-old Roman road connecting the empire.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

Manhattan's Thirteenth Avenue was made on landfill then deliberately destroyed — apart from one small, obscure block.

The one-time epicenter of American songwriting is now a little remembered Manhattan commercial block.

Cryptic messages embedded in the New York City sidewalk.

The origins of midtown Manhattan's anachronistic wooden farmhouse remain a mystery.

Elevated freight railway turned wildly successful urban park.

The only remaining building in New York to see the inauguration of a president is being slowly overtaken by a grocery store.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

Constructed in the 1920s, this former pencil factory is now an office building.

The most loyal of little dogs, or a Victorian era publicity stunt?

A blooming house of worship for the masses.

World's most expensive home.