Police say a man is in critical condition after plummeting 50 feet off a footbridge and onto an on-ramp for Boston's Storrow Drive.
The man, who police believe to be in his 20s, has not been identified.
Witnesses say the man had been leaning against a wall on the Arthur Fielder Footbridge when he apparently did a back flip over it.
Police do not know whether the man fell or jumped.
Anyone with information about the incident or the victim's identity is asked to call state police at (617) 727-6780.
