This multi-level, aqueduct-footbridge hybrid is one of the greatest works of the Spanish Renaissance.

Stormy conditions send jets of seawater bursting through holes in the cliffs.

These magnificently sculpted tombs represent Spain's own legendary version of "Romeo and Juliet."

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

A roadway designed for a visiting monarch.

Now home to a drinking establishment, this building has a macabre history.

A historic fire call point.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

This airport also offers travelers the chance to view thousands of years of Turkish history.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

The former headquarters of history's oldest megacorporation.

Once home to one of the oldest banks in the world, this building is also where Marco Polo's famous travelogue was written.

This 15th-century structure had a long, tortuous journey to its current location.

A sculpture in a secluded garden honors one of Edinburgh's most innovative thinkers and city planners.

This fountain is dedicated to the workers who perished constructing the Fréjus Rail Tunnel.

Scotland's first Masonic lodge may also be the oldest in the world.

This small church was constructed over the ruins of three temples dating to the Roman Republic.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

Neon artworks light up this dark Edinburgh tunnel.

A rare example of a medieval house in Rome adorned with a melancholic inscription.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

This large, circular tomb is the final resting place of the first emperor of Rome.

A rare and unique example of an 18th-century door latch calls this restaurant home.

An ancient Roman temple first dedicated to an emperor's wife is now a church.