This extinct volcano rises above Edinburgh and is special for its panoramic views over the city.

The world's first combination ski slope and power plant.

The grounds and buildings of an old wood pulp mill have been transformed into an innovative art park and museum.

A stairway to heaven, or to nowhere at all.

The patron saint of spinsters grasps a container of dried blood.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Something's watching you.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A space dedicated to contemporary art and culture, co-chaired by fashion icon Miuccia Prada.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

A museum that cashes in on its infamous little people while teaching you a thing or two about the Irish fey.

Climb inside an iron crystal magnified 165 billion times its normal size.

Now home to a drinking establishment, this building has a macabre history.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

The remains of the great moral philosopher reside in a university in London.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

This obscure walkway links Edinburgh’s Old Town with one of the city's prime vantage points.

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

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

A bizarre house filled with an astounding array of collections.

These delicate sand pyramids look like naturally occurring gothic spires.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

Austria's very first and only nuclear power station was completed but never used.