More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

The oldest public library in Ireland.

This permanent collection of preserved bodies taken from Irish bogs is one of the leading authorities on such morbid mummies.

One of Ireland's most infamous prisons for rebels including men, women and children.

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

These "anatomical machines" are only one of the many strange items in this Italian crypt.

An antique curios dealer and hybrid taxidermist.

A charming flea market shop dedicated to retrofuturistic apparati.

This museum in a Paris apartment gives a unique look at the iconic French singer's life.

Weird wax anatomical models reside here, as do other anatomical specimens.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

This massive library holds what was once the largest book collection in the world.

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.

This museum promotes informed contraception by documenting its often secret past.

One of the best collections of wax anatomical models in the world.

Macabre museum devoted to historical Viennese murders.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

The Habsburgs' royal collections of art and wonders.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Museum devoted to the artificial language of Esperanto.