Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

A historic Christian shrine nestled within a spectacular natural cave.

Giant topiary dog once played a role in a terrorist bomb plot.

A whimsical bridge uses saxophones to pay tribute to two great men and the European Union.

A massive, gleaming sea turtle with a rider atop its shell looks out over the horizon.

The location of the world's first telescope demonstration.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

This triumphal arch celebrating the Sun King's conquest of Lille is a masterpiece of military architecture.

The last Oostende trawler to fish off Iceland is now a museum.

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

Naturally formed rock city in Poland.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

This colorful statue welcomes visitors to a Barcelona park.

An early 20th-century bullring converted into a modern shopping center.

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

This narrow fjord-like bay is the largest ria in the Mediterranean Sea.

Extremely famous in his native country, this Cracovian painter is all but unknown beyond Polish borders.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

An underground city of salt.

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

Take a leisurely walk through the park to find the seven giant troll sculptures hidden throughout the park.

A man throwing a giant severed hand towers over Antwerp’s main square.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

This ghost town in Belgium will lose its street art when it ceases to exist.