This recently restored crypt was once plagued by liquefying coffins and exploding caskets.

Medical history with an amazing, if frighting, collection of wax diseases on display.

The relics of dozens of martyrs are stored in a single chapel.

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

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

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Large miniature theme park with 100-plus models.

Mummified monks and the accidentally interred, in a 17th-century crypt.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.

A narrow opening between the mountains of the Amalfi Coast creates a scenic hidden beach.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

Egyptian treasure trove of fossils documenting the whale's transition from land mammal to sea creature.

This ramshackle ghost town is comprised of mining-era buildings collected from around the region.

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

Residents of this Brooklyn neighborhood may be unaware their houses sit atop a buried trolley graveyard.

A once-secret library of Freemason history in Catalonia.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

This complex of vertically-excavated Buddhist, Jain, and Hindu monolithic temples in India's Maharashtra providence illustrates a spirit of tolerance characteristic of ancient India.

A Roman spa buried deep beneath the City of London.