A vintage fire engine is hidden inside this World War I-era water tower.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

These engineering masterpieces are a dominant feature of the Belfast skyline.

One of the largest lenses of its kind ever created, this former ship beacon has been brought down to Earth.

A museum marks and documents the site of the Titanic's launch.

These barriers stand as stark reminders of Northern Ireland's troubled past.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

It was once nicknamed "the most bombed hotel in Europe."

This massive monument has been telling the time for 150 years—at a slight angle.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

The last Victorian market in Belfast.

Locals affectionately dubbed this World War I memorial "Tommy."

A miniature train-ride through Slovenia's largest cave system.

The "dragon babies" of southeastern Europe.

This abandoned Slovenian military barracks has become a punky-political art squat.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

These carved, weathered stones once gave mail carriers and pub goers a leg up.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

The curious and tiny collection contains some very odd objects.

One of England's oldest stone churches and the birthplace of the "father of English history."

360° views of the city plus five floors of optical illusions and hands-on science.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.