A prisoner of war calculated exactly when ice ages should occur

Held during WWI, Serbian engineer Milutin Milankovitch calculated how slow cyclical wobbles in Earth's orbit, axial tilt and precession change sunlight reaching high latitudes over tens of thousands of years. His theory predicted the timing of past ice ages decades before ocean-sediment cores confirmed it in the 1970s. Milankovitch cycles remain central to explaining Earth's climate history today.

— Milutin Milankovic, Canon of Insolation and the Ice-Age Problem — Royal Serbian Academy, 1941