The modern birthplace of Irish freedom.

The world's longest wildlife overpass provides Hilversum's critters with a safe alternative to trying their luck on the roadway.

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.

The unusual stilted beacon is the town's only active lighthouse.

The bombed out remains of the old church were kept intact next to the new one, as a reminder of the futility of war.

This ruin in a suburban park may be the place where Shakespeare's "A Midsummer Night's Dream" was first performed.

An abandoned 14th-century castle and prison complex on a small island in the Neva River.

This Roman amphitheater is said to be King Arthur's legendary Round Table.

A village of art and exotic creations.

The former global standard for the exact mass of one kilogram sits under lock and key outside Paris.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

A fantastical 13th-century fortification sandwiched by a modern hotel in central Brussels.

This restaurant was removed from the famed sister ship of the Titanic and placed within a hotel.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

A network of concealed passageways lies within a busy London Underground station.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

England's steepest street has such a drastic incline that locals tie their parked cars to lampposts when it gets icy.

The abandoned funicular tunnel was a secret base for the BBC during World War II.

Nearly 2 billion seeds from 38,000 species are stored and processed at this visitable facility in a quiet corner of England.

Grab a cuppa at England's first and only domestic tea plantation.

The secret wartime bunker built on the platforms of an abandoned Tube station.

This abandoned gun tower was built to defend the River Thames from a French naval attack.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.