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

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

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

This overgrown Victorian chapel made of corrugated metal looks utterly out of place.

Don't be fooled by this fake medieval facade even if it is almost 300 years old.

With lush plants and flowers, huge trees, ponds, and hidden monuments, this place feels a bit like discovering Narnia.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A beautifully eclectic mix of architectural styles.

The attic of a four-century-old canal house hides a clandestine church.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

Replica of an old Esso filling station, complete with Wayne gravity pump and outhouse.

This bare tree might not have leaves but it is constantly clothed in festive decorations left by mysterious local benefactors.

The only free-standing, vertical sundial in the US was keeping standard time before it was even invented.

This small museum dedicated to the painful memory of segregation is essentially a time capsule.

The highest point in South Carolina was once owned by an energy company that neglected it but now the state is taking it back.

The world's largest fire hydrant is supposedly tornado-proof.

A hobby born from insomnia has turned into a hangar full of objects that have been be-buttoned by the Button King.