One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Rising from the sea like a stone monster.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

Medicinal spa created with the discharge from a geothermal energy plant.

A tribute to the incredible generosity the Choctaw Nation showed the Irish people during the Great Famine.

The Grand Lodge of Ireland is one of the oldest in the world, full of fantastical, elaborately themed rooms.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The oldest housing complex in Riga is a mini timeline of architectural trends.

The ancient tomb acts as a calendar that keeps perfect time.

The first museum dedicated to exploring humanity's cultural relationship with the celestial world.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

This Stone Age solar temple aligns with the sun on each equinox and solstice.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

Museum dedicated to "the man who moved the Earth."

This man-made mound monument was built out of soil from all across the Polish empire.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

A curious cave church carved into the face of a cliff.

Poland's oldest surviving university building holds a wealth of historic science instruments including some used by Copernicus.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

A majestic hotel for dreamers rises from the center of a fairytale wood.