The Figures of Note series of gold-plated 99.9% pure silver, proof quality coins depict historic figures as they were originally represented on Australia's first decimal currency notes issued between 1966 and 1974. The reverse of this coin depicts Sir Charles Kingsford Smith (1897-1935), Australia's famous aviator, whose record achievements included the first successful flight across the Pacific and the fastest flight from Sydney to London; and Lawrence Hargrave (1850-1915), the astronomer and aeronautical pioneer who worked on curved aerofoils, the box kite and the rotary engine as a means of powered flight. Australia's first twenty dollar banknote featured the image of Kingsford Smith on the front and the image of Hargrave on the back. The reverse design, which includes a coloured background, also incorporates The Perth Mint's 'P' mintmark. .