Where commuters walk through remnants of an ancient Greek necropolis.

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

Large collection from the 3rd millennium BCE.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Where Venice's gondolas go for a tune-up.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

The small peaceful island off the Venice tourist circuit is where the city began more than 1,500 years ago.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Part of the medieval watchtower is displayed in an otherwise ordinary parking garage.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

An ancient Egyptian temple in the middle of Madrid, Spain.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

They squeal, they nosh, they look like predators.

In paradise, feral pigs have claimed an island all to themselves.

The only castle in North America to ever house European sovereigns.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

Frida Kahlo's childhood home, now a museum of her life and works.