An underground city of salt.

An artificial hill and apparent calendric structure built in the Early Middle Ages immortalizes a legendary Polish princess.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

This man-made mound monument was built out of soil from all across the Polish empire.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

Mountain where Jesus was first tempted by the Devil.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Long tunnels run under the ancient chariot racing circuit to the tower.

This Roman arena once played host to bloody gladiatorial battles.

This memorial, built by fascist dictator General Franco in 1960, has been repurposed by the people of Catalonia.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

An ancient Roman theatre restored to its former glory in the Spanish city of Cartegena.

A monument at Alicante Marina honors a little-known hero of the Spanish Civil War.

Legends surround this natural rock formation that looks like a Moorish king wearing a crown.

A celebration of solstice followed by a fiery purging of evils.

This magnificent market stands as a poignant symbol of the suffering caused by the Spanish Civil War.

Down this yellow brick road, visitors are treated to toadstool houses and massive mushroom sculptures.