Thompson's Coins of Melbourne, #Australia regularly post interesting YouTube videos. They just posted one on a fascinating Australian #banknote I'd never heard of before - an early polymer test banknote from the 1970s! Yes, that early! Australia did issue the world's first circulation polymer banknote - but not until 1988, so this is an amazing piece of history. Check it out here: https://www.youtube.com/watch?v=oh4_dTzIhtk