The famous illusionist stood at the edge of the bridge. His hands were handcuffed behind his back and chained to a collar around his neck. According to a Boston Globe article chronicling the feat, a signal was tooted from a towboat, and Houdini went overboard into the chilly waters below.
The Globe estimated some 20,000 spectators gathered to see Houdini’s leap, including the mayors of Boston and Cambridge. They waited 40 seconds for the magician to resurface, which he did with the shackles in his hands.
A plaque commemorating Houdini’s jump is situated on the Boston side of the bridge, commissioned by Boston’s chapter of the Society of American Magicians. This plaque dates the escape as May 1, 1908. Other sources give the date as April 30, 1908.