Shimmering sea-colored mosaics and Jesus statues cover this opulent building.

A small pack of an ancient, hairless breed of dog once believed to guide souls through the underworld lives on its grounds.

Experience what life was like in Ireland during the Viking and medieval ages.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

A 600-year-old mini shrine guarded by a sword-wielding knight hides in a crumbling cliff face.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

Built during the Scottish boom in the oil industry, the village was never inhabited.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

The largest preserved walking dragline excavator in Western Europe.

Built by prisoners of war, the largest small-scale model ever built includes eight miles of tiny streams that now sit abandoned.

The deepest hole drilled in the name of science, where evidence of Precambrian life was found.