This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Brought to you by the makers of fiberglass dinosaurs.

A statue honors the children who fought Nazis in Poland.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

An intricately carved Viking church overlooks a glistening fjord.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

This Netherlands museum holds a gloriously mechanical collection of ornate musical automata.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

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

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

Museum celebrating the ocean, with the largest wunderkammer dedicated to sea exploration.

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

Overshadowed by other, more famous Maltese catacombs, this ancient burial chamber has one of the best examples of a ritual agape table.

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

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

Museum deep in the catacombs of St. Michael the Archangel Church is explored by touch, sound, and smell.

A narrow strip of land is home to the tallest migrating dunes in Europe.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

The statue of a legendary giant who carried Christ and shouldered the world's sins.

A black cat protests the City Guild in Riga's Old Town.

Why a column on the entrance is inscribed with a verse from the Quran is one of Sicily's many mysteries.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.