Birth Anniversary: Otto von Guericke — November 20, 1602

Otto von Guericke, physicist and mayor of Magdeburg, was born there on 20 November 1602. He rebuilt the city after the catastrophe of 1631, when imperial troops burned it to the ground during the Thirty Years’ War, and in 1654 demonstrated the force of atmospheric pressure by having teams of horses fail to pull apart two bronze hemispheres held together by nothing but a vacuum. Magdeburg’s cathedral, one of the few medieval buildings to survive that fire, watched both catastrophes and the science that followed.