From groundbreaking discoveries to sobering reminders of war’s destructive power, this day has left an enduring mark on world history. The First Atomic Bomb Used in Warfare (1945)On August 6, 1945, the United States dropped the atomic bomb “Little Boy” on the Japanese city of Hiroshima during World War II. The bombing, followed three days later by the bombing of Nagasaki, contributed to Japan’s surrender on August 15 and the end of World War II. Viking 2 Lands on Mars (1976)NASA’s Viking 2 spacecraft successfully landed on Mars on August 6, 1976. Hiroshima’s Peace Memorial (Atomic Bomb Dome) has been preserved as a UNESCO World Heritage Site.