The document discusses Albert Einstein and his achievements for which he was awarded the Nobel Prize in Physics. Einstein was a German-born physicist and scientist who developed the theory of general relativity in 1915, which re-formulated the concept of gravity. In 1921, Einstein received the Nobel Prize in Physics for his work explaining the photoelectric effect and contributions to theoretical physics, not for his theory of relativity which was not fully understood at the time. Einstein is considered the most popular scientist of the 20th century.