In the 1940s, the Italian Alpine Club popularized the Apollonio, a metal shed arrayed with guy wires. The structure, named for the engineer who designed it, was tiny but could sleep up to 12. It remained the standard alpine hut for 40 years, and dozens are still in use. Leap Factory’s Stefano Girodo, who worked on Gervasutti, pictured here, calls it “a masterpiece of industrial design.”