Alan Turing
Alan was a brilliant mathematician and cryptographer. He became the founder of modern-day computer science and artificial intelligence. He designed a machine at Bletchley Park to break secret Enigma encrypted messages used by the Nazi German war machine to protect sensitive commercial, diplomatic and military communications during World War 2. This made the single biggest contribution to the Allied victory in the war against Nazi Germany. It possibly saved the lives of an estimated 2 million people, and shortened World War II.