Which event finally brings an end to WWII?

Japan surrenders after the Soviet Union enters the war which marked the end of ww2.

Explanation: Nuclear weapons shocked Japan into surrendering at the end of World War II, which they didn't. Japan surrendered because the Soviet Union entered the war. Japanese leaders said the bomb forced them to surrender because it was less embarrassing to say they had been defeated by a miracle weapon.

Atomic Bombs

Explanation:

The two atomic bombs released on Nagasaki and Hiroshima ended WWII.

thomas jefferson is the answer

four sitting presidents have been assassinated while in office but the first was abraham lincoln,