This cover was mailed from my sister Denice who was living in Hamilton, NSW at the time to my mother who was living in Asquith NSW. We worked out that it contained wedding photos from my sisters wedding from 12 months before.
One Saturday in 2022 I was at a meeting at the Northern Philatelic Library in Minneapolis MN. The presenter was running late and we were all just sitting around chatting. My friend Brian was looking through a box of covers that were for sale at the Library and he brought this cover over to me, saying with a big smile on his face, "This must be one of your relatives ... ha, ha". In my amazement I said back to him, "well, it is addressed to my mother and it was mailed by my sister". How a cover mailed in Hamilton, NSW in 1973 made it's way to a little philatelic library in Minneapolis MN, 48 years later, is beyond my understanding.