This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

The first museum in the world devoted to sexual gadgetry.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Walk through Czech history in Prague's largest graveyard.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

The bones of some 7,000 soldiers killed in the historic Battle of Solferino are stored here.

An exclusive waiting room built for the royal family in the 1920s is hidden in Milan’s central station.

Nestled in the heart of Milan is a real wunderkammer of morbid curiosities.

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

Long-abandoned art nouveau baths beneath Milan's Piazza Oberdan.

A Milanese café entirely designed by the American director Wes Anderson.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

This modern arts center is built around a gem of late-Baroque architecture.

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

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

Lavish royal estate punctuated with heated greenhouses.

Although rarely used, there is still a hidden room for the royal family at the Stockholm central station.

A curious collection dedicated to human and animal anatomy and pathology.

Inside this church are the alleged remains of the patron saint of lovers, epileptics, and beekeepers.

Haunted tuberculosis hospital built by the patients.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

For six months of the year, three giant mirrors direct a pool of sunshine onto this otherwise occluded town.