Harry S. Truman was the 33rd President of the United States, serving from 1945 to 1953. He became president after the death of Franklin D. Roosevelt and is best known for making the decision to drop atomic bombs on Hiroshima and Nagasaki, effectively ending World War II. Truman also implemented the Marshall Plan to aid in the reconstruction of Europe after the war and played a key role in the founding of the United Nations. He was known for his straightforward and decisive leadership style and is often remembered for the famous slogan "The buck stops here."