A mysterious artist-run cabinet of curiosities and library.

An incarceration museum on the spot of possibly the oldest prison in England.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

Catacombs turned marketplace.

A student driver's nightmare.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

Steaming blood-red hot spring from hell.

A 20-meter (65-foot) robot towers over Tokyo Bay.

An exquisite tunnel of cascading flowers.

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

A Japanese video game arcade hides in the back of a Swedish pool hall.

Hidden behind a wall for decades, this masonic lodge was only rediscovered during renovations.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

A rare tour of an aristocrat's private home reveals valuable 17th-century paintings from artists like Rembrandt.

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

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

100-year-old shipwreck you can walk up to at low tide.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

This slice of 1960s Danish modernism does not conform to the Oxford college stereotypes.

One of Europe's oldest libraries.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

The television series' iconic giant foot was borrowed from this classical painting.

A network of concealed passageways lies within a busy London Underground station.

London's old-school healing garden.