This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

An Iron Age fort on the edge of a seaside cliff offers a glimpse into an ancient, mystical world.

This Transylvanian church has changed its denomination four times.

Check out engineering marvels of the past at this unintentionally retrofuturist museum.

Romania's triumphal arch looks out over Bucharest.

Known as the Hintz House, this medieval pharmacy has been an apothecary's haven for nearly 450 years.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

This bone-filled cave got its name after they found 140 bear skeletons inside.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

This massive underground salt mine now holds a sci-fi theme park in its depths.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A spooky spot along the road where things mysteriously seem to move uphill by themselves.

A countryside Romanian cemetery filled with colorful crosses bearing lyrical, ironic, or satirical rhymes.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

Belfast's namesake river still winds below the city center, hidden from sight.

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

This snug medieval lane is one of the narrowest streets in the world.

A medieval church built up to defend its village.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

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

A stunning Victorian abbey and walled garden on a lakefront.

An Irish town has built a statue to a silent film actor simply thanks to the holidays he once spent there.

A particularly disconcerting tribute to Irish martyrs.