"The prettiest love letters in the world" ... or so said Lord Byron.

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

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

An alchemist's "magic door" stands in the middle of a Roman park.

A fairy tale castle in modern Rome.

Tiny communists hammer away on the Olomouc Astronomical Clock.

A small man-controlled waterfall powers an Art Nouveau elevator and is accessed via narrow gauge, solar-powered tramway.

A church of bones, decorated with 40,000 human skeletons.

Microscopic scenes; some call it novelty, some call it art.

Two stunning 17th-century libraries and a cabinet of curiosities.

This unusually shaped mountaintop tower looks like a UFO floating over the city.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

Macabre astrological automaton clock dating to the late 1400s.

Monument to a suicide protesting the Soviet invasion.

A miniature city, once ruled by the Queen of the Netherlands.

A former plague hospital turned medical museum.

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

Oldest Museum of the Netherlands is a true cabinet of curiosities.

The spectacular history of spectacles on display.

Cat art as far as the eye can see.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.