On This Day in History, June 15 is marked by major milestones that shaped law, science, warfare, exploration and global culture. The sealing of Magna Carta in 1215 stands as one of the most influential moments in constitutional history, symbolising resistance to absolute authority. The day also witnessed early breakthroughs in medical experimentation with the first documented blood transfusion in 1667. In later centuries, June 15 saw decisive wartime action during World War II, landmark advances in aviation and industry, and defining cultural and political developments across the world, making it a historically significant date across eras.
