2018 $5 Land Sea Air Silver Coloured Proof Triangular CoinComprised of the Australian Army, the Royal Australian Navy and the Royal Australian Air Force, the Australian Defence Force is the tri service military organisation responsible for the defence of the nation by land, sea and air. Since Federation in 1901. Australians have committed themselves in arduous and dangerous conditions, in conflicts that include the Boer War, the First and Second World Wars, Korea, Malaya, Vietnam, Iraq and Afghanistan, and