Longest fortress system anywhere in Europe.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

Picturesque basketball courts sheltered by historical defensive walls and with an enviable sea view.

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

The only known mosaic depicting the Greek god of sleep, Hypnos.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Fortified medieval tower house with lovely roof garden.

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

At more than 5,000 years old, these structures are among the oldest free-standing stone buildings in the world.

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

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

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

This is one of the very few intact windmills built by the Knights of St. John in the island nation of Malta.

These temples are among the oldest free-standing stone buildings in the world.

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

This tiny island is recognized as the site where St. Paul landed after a shipwreck in the first century.

It houses the remains of a 17th-century version of the Titanic.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

A quiet grave marks the site of a centuries-old fairytale love story that turned out to be a real murder.

This ducal residence was once home to a future Russian empress and a French king in exile.