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

A grotesque collection of wax limbs depicting the symptoms of venereal disease.

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

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.

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

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

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

This museum houses an imposing skeleton army comprised of creatures great and small.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

One of the deepest indoor swimming pools in the world.

A rare example of World War I trenches from the British front.

This Belgian palace was long the domain of priests and aristocrats but is now being turned into an art commune.

Tintin's creator is celebrated in an immersive museum that's an astounding work of modern art.

The former home of a trailblazing surrealist is still filled with haunting dolls and grim paintings.

Inside this former medieval prison is a collection of objects designed to inflict unbelievable pain and suffering on the human body and mind.

Most prolific publishing house in the 1600s open to the public.