Albert Einstein was a theoretical physicist born in 1879 in Germany. He is best known for developing the theory of relativity, which revolutionized our understanding of space, time, and gravity. His famous equation, E=mc², illustrates the relationship between energy and mass, making significant contributions to modern physics. Einstein's work earned him the Nobel Prize in Physics in 1921 for his explanation of the photoelectric effect. Beyond his scientific achievements, he was also an advocate for civil rights and pacifism. He passed away in 1955, leaving a lasting legacy in both science and humanitarian efforts.