An early Portuguese serial killer's head is alarmingly well preserved in a jar at the University of Lisbon.

There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

Elevated freight railway turned wildly successful urban park.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Tucked in the back of this amazing antique store is an important piece of medical history.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

A kaleidoscopic warehouse-maze of handmade neon signs.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

A house of bones — but nobody is quite sure to whom they belong.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

The anatomical-pathological collection of a man who changed surgery.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.

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

Europe's second largest ossuary wasn't discovered until 2001.

A cheeky architectural easter egg.

A peculiar clock commemorates a historic victory won by ringing the noonday bell an hour early.

This hanging crocodile is thought to be the "dragon" that once plagued a Czech city.