Albert Einstein is one of the most written-about figures of the 20th century, and for good reason. His theories upended the system that physicists had used to describe the world since Newton.

Albert Einstein was born in Ulm, Germany, on this day in history, March 14, 1879. He was just 26 years old when he proposed his groundbreaking theory of relativity.

Albert Einstein profoundly changed physics and ideas about space and time. ... The second wonder came at age 12 when he discovered a book of geometry, ... according to his Nobel Prize biography.

Albert liked doing puzzles, reading books about nature, and playing violin. He was fascinated by the invisible magnetic force that makes compasses work. And he was very curious about math.