Close-up of the solar furnace at Odeillo in the Pyrenees-Orientales, France. The concave mirrors on the nine-storey building can be used to focus concentrated sunlight onto the tower in front which contains the solar furnace. The resulting temperatures of up to 3,500 degrees Celsius are used to research the effects of high temperatures on various materials. The facility, which houses the PROMES laboratory, was designed by Felix Trombe and opened in 1970.