While lying on the beach in Nice one day, eighteen-year-old Yves Klein and his friends decided to divide the world up among themselves. Klein (1928-1962) chose the air, the cloudless sky. He remained fascinated with the element and its immaterial quality throughout his life. In the late fifties, he and the German architect Werner Ruhnau developed plans for an "architecture of air" composed of walls and roofs of air-as represented, for example, in the idea of the "Temple of the Elements" with fountains of water and fire and a café protected against the rain only by air currents.