UPDATE 1-Facebook's Zuckerberg urges Harvard grads to contemplate risk
May 25, 2017 at 16:26 PM EDT
CAMBRIDGE, Mass., May 25 (Reuters) - Facebook founder Mark Zuckerberg returned on Thursday to Harvard University, the school he dropped out of to start the pioneering social network, to urge its graduating class to help create a new social safety net to allow creative risk-taking.