At the beginning of the 20th century, the first aircraft manufacturers used aluminium for its low density and lightness. However, research was carried out with other alloys to increase its mechanical properties. In 1906, the German Alfred Wilm invented Duralumin, an alloy of aluminium, copper, manganese and magnesium. Duralumin was the material of choice for aeronautics and was used long after the Second World War. Built in Duralumin, the Breguet 14 was manufactured until 1926. Only two examples remain in the world today, in the Air and Space Museum (photo) and the National Museum in Helsinki (Finland).