1 Crown - Elizabeth II The Battle of Passchendaele

Passchendaele — officially the Third Battle of Ypres — ran from July to November 1917 and produced roughly 500,000 combined casualties across the Salient, with British and Commonwealth forces gaining less than five miles of waterlogged ground. The centenary year prompted a wave of commemorative issues across multiple jurisdictions, and Tristan da Cunha, a British Overseas Territory with a population under 300, has become a reliable vehicle for the Pobjoy Mint's commemorative programs precisely because its crown-issuing authority requires no domestic monetary infrastructure.