An underground city of salt.

The Stonehenge of Wales is one of the grandest neolithic dolmens still in existence.

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

The highest peak in Wales is said to be the final resting place of a giant killed by King Arthur.

A sweet symbol marks the place where torturous executions were once carried out.

The taxidermy remains of the first mammal ever cloned from an adult cell are on display in Edinburgh.

Three bridges straddle a stream, one stacked upon the other.

A miniature Italianate fantasy village on the coast of Wales and the set of ITC classic "The Prisoner."

Largest lake in Great Britain measured by surface area.

The pioneer of psychoanalysis spent the final year of his life here, still seeing patients on that famous couch.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

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

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Giant, friendly pelicans in Central London, the most unlikely of places.

A rocky sea serpent hides caves, blowholes, and a spectacular natural bridge.

A collection of comics, graphic novels, animation and caricatures devoted to exploring this often overlooked art form.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

360° views of the city plus five floors of optical illusions and hands-on science.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

A museum dedicated to the former country.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.