Albert Einstein was born in Germany in 1879 and showed early aptitude for mathematics. He struggled in school and was expelled from one. He later published groundbreaking work on physics including the photoelectric effect and his special theory of relativity which introduced the famous equation E=mc2. He immigrated to the United States in the 1930s and became a U.S. citizen. Einstein worked to promote peace and opposed the development of nuclear weapons. He died in 1955 at the age of 76.