Nitrogen fertilizer

Fritz Haber found how to pull nitrogen out of the air and fix it as ammonia; Carl Bosch built the plant that did it at industrial scale. Synthetic fertiliser followed, and with it the food that feeds roughly half of everyone alive — no single discovery has kept more people from starving. The same man also directed Germany's chemical-warfare programme in the First World War and personally supervised the first chlorine gas attack at Ypres in 1915, over his wife's protest. He was driven out of Germany in 1933 for being a Jew and died in exile the following year. Both facts are his; the bread is what this wall is thanking him for, and the record is stated whole.

Part of “The Gifts of the Jews” — verified Jewish contributions to the world, with sources.