In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

Floating pink tap installed for a flower show in London.

A museum and gardens with unusual plants and a history of progressive programming for the blind.

A million and a half tons of earth were used to create one of the world's largest land sculptures.

This enchanting Victorian estate was home to the world's first hydroelectric power generator.

This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

The sign at the garden gate reads: "These Plants Can Kill."

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

The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.

A secret garden in a picturesque Edinburgh village has inspired artists for centuries.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

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

The mystery of this small, brick pond eluded its possibly only investigator until his death.

Harry Potter once visited this massive limestone cliff, which was carved by an ancient glacial river.

A 30-acre garden inspired by the principles of modern physics.

Local legends say that fairies used to dance in the moonlight here and invite handsome young men into their grottoes.

The highest peak in all of England is plagued by dangerously fickle climate shifts.

The largest cave chamber in Britain—big enough to fit a whole cathedral inside.

A giant pineapple, a symbol of hospitality, and an amazing vacation rental option.

The heads of two giant mythological water horses honor Scotland's horselord past.

A 200-year-old collection of oddities and medical paraphernalia.

Largest lake in Great Britain measured by surface area.

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

6000-year-old site covered in more than 50 megaliths.