One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

The largest oak in England is said to have been the hideout of Robin Hood and his Merry Men.

Highly spherical boulders on the shores of New Zealand.

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

There might not be much left of these Irish ruins, but their linguistic legacy is still going strong.

Cliffs full of fossils at the portal to England's Jurassic Coast.

A chapel on a volcanic core, marking the end of a successful journey.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

The lake that fills and empties itself at random.

An intriguing three-sided folly is a testament to one man's devotion to Catholicism and the number three.

Bridge that died in war and was resurected.

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

An Italian geologic wonder that served as the inspiration for the landscape of Dante's hell.

The abandoned village of Skarð aptly illustrates the idiom "Don't put all your eggs in one basket."

This Tuscan lake hides a 13th century town that is still visible when the water recedes.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.

The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

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

The oldest inn in Kilkenny was established by the first convicted witch in Ireland.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

This picturesque archeological site looks like it was pulled straight from a fantasy novel.