September 1 in History

On 1 September 1923, a powerful earthquake struck the Kanto plain of Japan, devastating Tokyo, Yokohama, and surrounding prefectures. Estimated at magnitude 7.9, it triggered fires, landslides, and a tsunami, and killed roughly 100,000 to 140,000 people, with the figure often given as around 105,000 in later studies. It remains one of the deadliest natural disasters in Japanese history, and it reshaped both the physical form of the capital and Japan's approach to disaster preparedness.

World War II began in Europe on 1 September 1939, when Germany invaded Poland, and ended in 1945 after becoming the deadliest conflict in human history. Britain and France declared war on Germany two days later, turning a regional attack into a general European war that would eventually spread across Asia, Africa, and the oceans. Estimates of the dead vary, but most historians put the total at well over 60 million people, a majority of them civilians.