This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

These "mermaids" that surround a plaza in Segovia are rather sphinx-like.

This influential Renaissance-era library was once the haunt of kings and monks.

An ode to the famous Las Vegas signage.

These Bullet-scarred bunkers are haunting reminders of the Spanish Civil War.

This 18th-century project to build the world's tallest gravity dam was never completed.

Sometimes called the Banksy of Madrid, Muelle was a pioneer of street art in the Spanish city.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A devastating landslide accidentally created this tourist hotspot.

One of the tallest lighthouses in the world also serves as a monument to the fallen of World War I.

When a massive landslide hit one of the world's tallest dams it created a tragic environmental disaster.

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

This small island off the coast of Uruguay hosts the largest colony of sea lions and fur seals in the southern hemisphere.

Perhaps the most spectacular grotto along the Algarve coastline.

An Irish cemetery filled with victims of political strife and violent conflict, including the grave of Bobby Sands.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

Two standing giants remain as a tribute to Luxembourg's metallurgical past.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

A preserved college lock-up that recalls a clubhouse approach to discipline.

Walk inside a half mile long crevice right outside the town of Garmisch Partenkirchen.

A small but immensely extravagant palace built by the "Night King."

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.