This striking sculpture of Icarus honors Greece's fallen flyers.

These caves secretly held national treasures during World War II.

The oldest standing Byzantine church in Athens is tucked within a monastery in the middle of an upscale shopping district.

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

A Byzantine-era church hidden in a wooded area below the Acropolis.

Where commuters walk through remnants of an ancient Greek necropolis.

The ruined doorway is a portal to the building's turbulent and torturous past.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

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

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

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

An ancient octagonal weather station named for the eight Greek gods of wind.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

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

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.

The heads of two giant mythological water horses honor Scotland's horselord past.

The longest staircase lock in Britain.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

A close look reveals that the Scottish monument is just slightly off-kilter.

Now famous as the "Harry Potter bridge," this impressive concrete viaduct has long been an icon in its own right.