J. Robert Oppenheimer, born on April 22, 1904, was the scientific director of the Manhattan Project, the World War II project that developed the first nuclear weapons. He strongly opposed the development of the hydrogen bomb.
After the assassination of Abraham Lincoln in 1865, the new president Andrew Johnson issued his own Reconstruction Plan. He announced that on the ratification of the 13th Amendment Southern states would be re-admitted into the Union. This upset Radical Republicans and impeachment proceedings were began against him.
Wilmer McLean - he had a shell burst in his summer kitchen at the First Battle of Bull Run, after which he moved to the small town of Appomattox Court House, where he was sure the war wouldn't find him or his family again. It was in his living room on April 9, 1865 that Generals Lee and Grant signed the surrender ending the War.