Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Carefully reconstructed after the Bosnian War, this 16th-century bridge stands as a symbol of the country's enduring multicultural heritage.

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

Northern Ireland's church-turned-skate park.

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

These gigantic skeletons tower over visitors and provide insight into the creatures that once ruled over Ireland.

The block of aged dairy is probably still edible after 2,300 years in a peat bog.

This courtly monument celebrates an influential comedian who turned taking the piss out of the powers-that-be into an art.

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

In 1943 the British military took control of this village, telling residents they had to leave temporarily. The villagers were never allowed to return.

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

This one has sailed five times as far as Sir Francis Drake's famous ship.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

An underground city of salt.

Gargoyle head that brings good luck.

Legend says this sacred tree was a gift from goddess Athena.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The final resting place for the remains of 143 Habsburg royalty.

Behind this pair of dragon trees, there is a tragic story of lost love.

This replica of Columbus's famous ship houses the history of La Palma's maritime importance during the Age of Exploration.

A lush oasis full of vibrant plants and striking geometric displays.

This glass skywalk offers vertiginous views down the volcanic cliffs to the beach below.