Albert Einstein’s name is almost synonymous with genius. The German-born theoretical physicist would have turned 138 on Tuesday, March 14, if he were alive.

Born in 1879 in Ulm, Germany, Einstein went on to become one of the greatest scientists in the mankind’s history. His work had major impact on physics. He developed the theory of general relativity and advanced the law of photoelectric effect. His work earned him a Nobel Prize in 1921, and in 1999, the Time magazine named him “Person of the Century.”

Apart from his work in physics, Einstein was also known for his civil rights activism. He is reported to have been aware of the similarities between American segregation and the treatment of Jews in Germany, leading him to fight racism in the U.S.

Einstein died April 18, 1955, from an abdominal aortic aneurysm in New Jersey.

Check out some of Einstein’s quotes from Goodreads and Brainy Quote to celebrate his birthday.

“Look deep into nature, and then you will understand everything better.”

“Anyone who has never made a mistake has never tried anything new.”

“Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.”

“If you can't explain it to a six year old, you don't understand it yourself.”

“When you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativity.”

“Science without religion is lame, religion without science is blind.”

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?”

“Try not to become a man of success. Rather become a man of value.”

“Once you can accept the universe as matter expanding into nothing that is something, wearing stripes with plaid comes easy.”

“The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking.”

“I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.”

“You never fail until you stop trying.”