A touching letter from Albert Einstein to students at a Brazilian college has been discovered after almost 65 years.
The typewritten note, which had been locked in the school safe, was written by the physicist in June 1951 from Princeton, New Jersey, to motivate pupils at Colegio Anchieta in Porto Alegre, Brazil.
Written in German and signed by -Einstein it reads: "He who knows the joy of understanding has gained an infallible friend for life.
"Thinking is to man what flying is to birds. Don't follow the example of the chicken when you could be a lark."
Einstein wrote the letter "to the students of Anchieta College, Brazil" at the request of the Jesuit father Gaspar Dutra, who met the scientist in New York while he was training.
Father Dutra brought the letter back to the school where it was kept in a safe and eventually forgotten. It was rediscovered when the college was preparing celebrations for its 125th anniversary.
Father Joao Claudio Rhoden, director general of the school, which has 3000 pupils and was founded in 1890, said the message of the letter was "beautiful".
"The man preoccupied with the Theory of Relativity and other things thought to write to young people from a city that maybe he never even imagined existed," he said. "This document has a very great value... in the message there, in this memento he gave to the students."