Before the first computer existed, he described it. Before the war ended, he helped end it. Britain repaid him with ruin.
In 1936, a 24-year-old wrote a paper describing a machine that did not exist — and in doing so, invented the computer. In 1940, he built machines that broke the Nazis' "unbreakable" code, and helped shorten the bloodiest war in history. In 1952, his country prosecuted him for being homosexual and destroyed him. Alan Turing gave the modern world its mind, and the modern world broke his.