A wunderkammer of gold and silver reliquaries and ancient saintly bones.

An ancient knight and a symbol of the city's freedom.

Gargoyle head that brings good luck.

This Croatian island is for sale but no one is buying due to the dozens of accused Nazi sympathizers who were massacred there after WWII.

Longest fortress system anywhere in Europe.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

An ethereal glowing blue ocean cave in Croatia.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

This ancient stone bridge dates back to the early Middle Ages.

This tangled English forest looks like something right out of a fairytale.

Eighteenth-century home, where Herschel discovered the planet Uranus.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

Warsaw's fantastically preserved gasworks...almost.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

An eccentric garden of sculptures crafted in India decorate an Irish green space dedicated to Alan Turing.

The tomb of history's greatest potato promoter is surrounded by tubers.

This ancient Irish landscape boasts hundreds of legendary ruins.

These gigantic skeletons tower over visitors and provide insight into the creatures that once ruled over Ireland.

This beautiful site is where the first transatlantic telegraph was sent from.

The world's only flying boat museum honors a small Irish village that sent 20th-century aviation to new heights.

This modest plaza in Moneygall, Ireland has cashed in on its distant connection to the U.S. president.

A massive Celtic cross secretly growing in an Irish forest.