Albert Einstein is often called the father of modern physics due to his groundbreaking contributions to various fields including theoretical physics, quantum mechanics, and cosmology. His development of the theory of relativity, which revolutionized the understanding of space, time, and gravity, remains one of his most notable achievements. Additionally, his famous equation, E=mc², established a fundamental relationship between energy and mass. Einstein's work laid the groundwork for much of modern physics and has influenced numerous scientific advancements since the early 20th century.