Hannsjörg Voth, Himmelstreppe, 1984

Since the early 1980s, the German conceptual and land artist Hannsjörg Voth has been making installations in the Moroccan desert, from a beguiling spiral fountain to a series of towers that replicate the constellation of Orion. This majestic sculpture, titled Himmelstreppe (or “stairway to Heaven”), is another such work: a wedge-shaped structure replete with 52 narrow stairs that passersby can theoretically climb to get closer to the sky. That said, Voth’s works are deliberately impermanent, so potential clamberers, beware.