The Shrine of Remembrance, not long after completion I think. I know nothing of the pool of water. Australia and New Zealand commemorate ANZAC Day with ceremonies around the two countries and in other countries too. Melbourne's major ceremony is held at the Shrine, with a dawn service and later a veterans march.
Mother on your right at the Shrine of Remembrance on, I assume, Anzac Day and with her best friend who died two years ago. I would guess it would be the early 1950s. Not sure that a newspaper under your arm is a great look Mother. Rest assured, as a good Presbyterian lass, she was not carrying the racing form guide. More likely for the City movie guide.
Note the lack of trees around the Shrine, unlike now, with just one distant gum tree to be seen. The path to the Shrine was only gravel then.
As flippant as I can be at time, I can't bring myself to say happy Digger's Day. For me it is a day to remember the hideous happenings of war and the millions of people around the world killed in the name of war, more often than not at the bidding of the rich and powerful. Lest we forget that the young of Australia and their parents will ever be so naive again. Make that the world.
Later Edit: I asked Mother about the photo today, and she confirmed it was Anzac Day. I asked who took the picture and she did not know. She guessed a stranger. She told me she thought it was a horrible photo of her and not to use it at her funeral.