Facebook founder Mark Zuckerberg has returned to Harvard University under rainy skies to give a graduation speech and receive an honorary degree.
The world's fifth-richest person, worth $62.3b (£48.1b), famously dropped out of Harvard after launching the global social-networking website.
Zuckerberg called for students to "not only create new jobs, but create a new sense of purpose".
Political experts think he may be positioning himself to run for office.
During his remarks on Thursday, Zuckerberg told graduates that "we live in an unstable time".
"There's pressure to turn inwards," he said about those that feel left behind by increased globalisation.
"This is the struggle of our time. The forces of freedom, openness and global community against the forces of authoritarianism, isolationism and nationalism."
With his wife, Priscilla, in the audience, he pointed to the dormitory where he launched Facebook, and remarked that meeting her there was the best thing to happen to him at the university.
Before giving remarks, he received an honorary Doctor of Laws degree during Harvard's 366th graduation ceremony.
