Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

A sharp sculpture made of thousands of pieces of jagged glass.

Where commuters walk through remnants of an ancient Greek necropolis.

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

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

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

A former military hospital is now used to study and preserve artifacts of the Acropolis.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

Legend says this sacred tree was a gift from goddess Athena.

This Ottoman-era church is hidden amid a busy tourist area.

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.

A Byzantine church containing the holy remnants of three saints sits atop the site of an ancient temple.

The railway carts travelers to central Athens's highest peak, which offers stunning vistas of the city.

A crushed gate and giant bronze head serve as a reminder of Greece's fight for freedom.

The oldest covered railroad bridge still standing in the United States.

This location of a Mexican chain restaurant has a unique location: an old jail.

Carved, egg-shaped stone with no explanation.

The 92-foot-tall structure is based on the aircraft that carried the first Americans into space.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.