What major event occurred on August 6 and 9, 1945?

The event that took place on August 6 and 9, 1945, was the atomic bombings of Hiroshima and Nagasaki. On these dates, the United States dropped atomic bombs on the Japanese cities of Hiroshima on August 6 and Nagasaki on August 9 during World War II. These bombings were pivotal moments in warfare, as they marked the first and only use of nuclear weapons in armed conflict. The bomb on Hiroshima resulted in massive civilian casualties and destruction, and it was followed by the bombing of Nagasaki, which further compelled Japan to surrender. This series of events ultimately led to the end of World War II, making it a significant turning point in modern history.

The other options do not relate to events from those specific dates; the invasion of Poland occurred in 1939, the signing of the UN Charter took place in 1945 but at a different time, and the Nuremberg Trials began in late 1945, well after these bombings.