Hugo Mendelson · CC BY-SA 3.0

Weizmann was a research chemist before he was a statesman: he developed a fermentation process that produced acetone from bacteria, which Britain used to manufacture cordite explosive propellant during the First World War, and the goodwill it earned him helped him press the British government toward the 1917 Balfour Declaration. As leader of the Zionist Organization he spent three decades building the case for a Jewish homeland, then convinced the Truman administration to recognize the new State of Israel in 1948. He became Israel's first president the following year, and the research institute he founded in Rehovot was later renamed the Weizmann Institute of Science in his honor.