The first United States patent is officially granted to inventor Samuel Hopkins for his method of making potash and pearl ash. The patent was personally signed by President George Washington and Secretary of State Thomas Jefferson.
The Third Battle of Ypres, commonly known as Passchendaele, begins in West Flanders, Belgium. The battle would become infamous for its brutal mud and high casualties, representing the horrors of trench warfare.
British author and philanthropist best known for writing the Harry Potter fantasy series, which has sold over 500 million copies worldwide and became the best-selling book series in history. Her work spawned a massive media franchise including films, theme parks, and merchandise.