A teenager drowned in the Charles River in Cambridge, Massachusetts, on Friday evening, police said.
Witnesses saw Tyler Greene, 18, go into the water, flail his arms and go under.
State police responded around 8:45 p.m. About 25 minutes after he went underwater, he was found by divers with the Cambridge Fire Department.
The teen was taken to Beth Israel Deaconess Medical Center, where he was pronounced dead.
"One by one police cars were arriving on this side and the other side of the brige and you could see people at the top with flashlights," said witness Nia Evans. "I was hoping that someone had not fallen in. Or that someone hadn't drowned. So it's truly sad to hear."
Greene had been a student at Harvard Summer School where fellow students said the bridge jumping happens frequently.
"Two of my friends did it before they left campus," said student Samantha Nevile. "It seems like a bucket list thing."
A growing memorial was present at the bridge on Saturday as fellow students stopped by to mourn.
"It's surprising because you don't think these things are going to happen, and it's really sad," said Nevile.
Cambridge police said foul play is not suspected and Green's death appears to be an accidental drowning. Authorities said it's not uncommon for people to jump off the bridge, although it's prohibited.
"I think people just jump off for kicks and then just swim out, and do it again," said Evans.
Sandra Naddaff, Dean of Harvard Summer School, released a statement on Greene's death:
"We realize how very upsetting this sad news can be even to those who did not know Tyler personally. We are all here to help. Don't hesitate to reach out to your proctor or Assistant Dean or any member of the Harvard summer staff if you wish to talk.
Our thoughts and prayers are with Tyler's family and friends in this difficult time."