Albert Einstein (1879-1955) was a German-born theoretical physicist who revolutionized our understanding of the universe with his theory of relativity. He won the Nobel Prize in Physics in 1921 for his explanation of the photoelectric effect. Einstein is best known for his mass-energy equivalence formula E=mc^2, which has become a symbol of modern physics. He fled Nazi Germany in the 1930s and settled in the United States, where he contributed to the development of the atomic bomb during World War II. Einstein spent the latter part of his life advocating for civil rights, pacifism, and international cooperation. He is considered one of the greatest scientists of all time and his work continues to influence physics and philosophy to this day.