In the southern Italian town of Matera, a system of natural caves called Sassi first inhabited during the Paleolithic Age has become a bustling tourist destination. It’s something of a full-circle moment for the city, which was once called “a national shame” by an Italian politician. Starting as a troglodyte settlement and then becoming home to peasants and artisans during the Middle Ages, Matera fell into squalor by World War II, with an infant mortally rate as high as 40 percent. The impoverished residents of the caves were forced from their homes but begged to come back, and in 1986, those who pledged to restore the Sassi were allowed to return.

As the Smithsonian notes, the locals here still “cheerfully refer to themselves” as troglodytes, a word that literally means “cave dwellers.” But the caves don’t exactly look prehistoric anymore. Once lacking even the most basic hygienic standards, they’re now beautifully lit, packed with contemporary artwork, designer furniture, flat-screen televisions, and all the other modern amenities you’d expect from high-end hotels anywhere in the world. That’s certainly true at the Aquatio, where smooth new limestone bricks merge seamlessly into the raw cave walls, now cleaned of lichen and brightened up to their original pale color.
The architects took inspiration from the powerful force that shaped the caves in the first place: a single drop of water. Honored near th...