A fantastic castle rumored to be the birthplace of King Arthur.

A whimsical cottage from the 1300s with a preserved Victorian-era post office inside.

A hermit's tiny cell built into the cliffside that saved him in South Pembrokeshire.

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

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

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

This Welsh village gave itself a ridiculous name in a publicity stunt a century ahead of its time.

Huge winged monument in the United Kingdom.

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

This giant wooden treehouse within a sprawling garden has its own eatery.

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.

These upturned herring boats make nifty storage sheds for fishing goods.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

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

The oldest house in Glasgow is now a museum dedicated to the city's medieval history.

Climb this overlooked gem's spiral staircase and you'll be rewarded with spectacular views of Glasgow.

A scattered trail of street art adds a pop of color to the city's stark structures.

Glasgow's memorial to the International Brigade volunteers from Great Britain who fought and died in the Spanish Civil War.

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

This Scottish bridge seems to compel dogs to leap to their death.

Old-fashioned knowledge and modern engineering create the world's only rotating boatlift.

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

At high tide this strange footbridge appears to have no purpose whatsoever.

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