Unknown author · Public domain

Warburg won the 1931 Nobel Prize in Physiology or Medicine as its sole recipient, for discovering the enzyme that lets cells use oxygen to convert nutrients into energy — foundational work in cellular respiration. He served as a cavalry officer in the elite Uhlans during the First World War and was awarded the Iron Cross for bravery. Over his career he was nominated for the Nobel Prize an extraordinary 48 times, though he won only once.