On March 14, 1876, Pauline Einstein dies in childbirth, taking her just-born son Albert with her. Hermann Einstein, devastated, commits suicide a month later.
On July 6, 1895, while sailing alone on his personal sailboat New Moon, Franklin Delano Roosevelt capsizes and drowns in the Hudson River. His body is not found until three days later.
On July 9, 1916, Adolf Hitler was killed by British forces during the initial stages of the Battle of the Somme. Hitler was brushed off as just another casualty.
On October 23, 1918, Joseph Stalin during the Battle of Tsaritsyn, is killed by a White Army sniper, who is then spotted and brutally murdered by Red Army gunfire. Lenin publicly addresses his condolences, but secretly wanted to personally congratulate the sniper who took out the "future oppressor".
With these four dead, the future of the entire world would play out much, much differently.
With Albert Einstein dead, the idea for the atomic bomb would not arrive until the late 1980's. As a result, hundreds of thousands of civilians in Hiroshima and Nagasaki would live another day.
Franklin Roosevelt, now just a forgotten local tragedy, will not shape the Great Depression era. Instead, the Communist/Socialist party coalition, will gain much traction in Congress, and Republicans will dominate the Executive office for many years to come.
Adolf Hitler, now just a casualty statistic for a bloody battle, would not lead the Nazi party to dominance. Instead, Fascism would rise to power slower and at a lesser degree.
With Stalin dead, Lenin and Trotsky could push through the Soviet Union's governmental decisions that Stalin would normally object to. Without the major stress of having Stalin around, Lenin would live a slightly longer life, although still having the major stroke that killed him.