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

The longest and tallest aqueduct in Britain can actually be sailed across.

Picturesque ruins once held off mighty armies.

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

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

A harem-inspired Moorish fantasy design in a Victorian-era Welsh castle.

This abandoned asylum in Wales might look haunted, but it's still beautiful.

The stately remains of Llywelyn the Great's mighty fortress.

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

This hilarious English intersection is an automotive whirlpool.

The first archaeological site discovered by aerial photography.

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

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."

65 million-year-old chalk outcroppings mark the end of the Jurassic Coast.

These stark white cliffs were spat up by the sea and are slowly being retaken by it.

England's most notorious suicide spot.

A metal tree emits eerie, melodic notes on top of Lancashire's Crown Point.

A movable feast that is an East London institution.

Shiny Brutalist box commemorates a pioneer of electricity and houses a railway transformer.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

A glorious pub known for a spiteful printing feud and its famous typeface lost—then found—at the bottom of the Thames.

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