Europe's official "zero-level," the equator of elevation.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

Amsterdam's former hotspot for public executions and dissections.

An overgrown and largely forgotten cemetery lies hidden within the outskirts of Amsterdam.

This unusual elevator doesn’t stop or slow down.

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

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

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

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

Visible at low tide, this rusting vessel is one of the last surviving examples of the X-Class "Midget" submarines.

This secret coastal village is studded with pastel-colored houses all piled on top of one another.

Scores of wax baby figurines add an unusual mood to this beautiful church on the Greek coast.

A dark, narrow tunnel that leads to a charming lake and waterfall.

Swarms of dainty flying insects swarm into the Petaloudes Valley to get busy.

This abandoned bridge over the River Irvine may be the oldest surviving railway viaduct in the world.

The oldest cemetery in Belgium.

This monument dedicated to the legendary American showman can be found in Scotland's largest city.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

A rococo room covered entirely in porcelain originally constructed for another royal residence.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

A surreal botanical garden with an even more surreal tour guide.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.