Observed on April 25, ANZAC Day is an antipodean memorial day, commemorating the past and ongoing contributions of Australian and New Zealand armed forces. The holiday's origin, however, was more specific. It was established in memory of the many Australian and New Zealand Army Corps (ANZAC) soldiers who lost their lives in Turkey during WWI, as part of a long, horrific, and ultimately unsuccessful campaign.
In many places, the sale or consumption of crispy golden cookies known as "ANZAC biscuits" will be as much as part of observances as poppies or parades or sunrise vigils. If it seems odd that there's a more-or-less official sweet treat associated with such a somber occasion, just consider how much comfort this humble taste of home must have given to those ANZAC soldiers.
The ultimate origins of the ANZAC biscuit are unclear (I found a similar recipe for "Canadian shortbread" dated 1933 in a vintage Australian cookbook), but it was a perfect match for the shortages and challenges of wartime. Made from oats, flour, shredded coconut, sugar, butter, baking soda, and water, the ANZAC biscuit calls for treacle or golden syrup as a binder, instead of then-scarce eggs. The biscuits were durable enough to ship, would keep for long periods without refrigeration, and--just as important--were both nourishing and delicious. Women in Australia and New Zealand packed ANZACs into whatever tins they had on hand and sent them off to the battlefields by the boatload.
ANZAC biscuits are now a popular year-round treat, manufactured by commercial bakeries as well as by home cooks. On ANZAC Day, biscuits are frequently sold to raise funds for veterans' services, continuing to provide comfort and sustenance for those who have served.