Albert Einstein (/ˈnstn/;[3] German: [ˈalbɐrt ˈaɪnʃtaɪn]; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist. He developed the general theory of relativity, one of the two pillars of modern physics(alongside quantum mechanics).[2][4]:274 Einstein's work is also known for its influence on the philosophy of science.[5][6] Einstein is best known in popular culture for his mass–energy equivalenceformula E = mc2 (which has been dubbed "the world's most famous equation").[7] He received the 1921 Nobel Prize in Physics for his "services to theoretical physics", in particular his discovery of the law of the photoelectric effect, a pivotal step in the evolution ofquantum theory.[8]