Globe photographer David L. Ryan, at the scene, reports that the first explosion occurred at the Marathon Sports store and sounded like a manhole cover had blown up. But then he smelled gunpowder. He said that explosion was very close to the bleachers set up on the sidewalk.
The next explosion occurred seconds later near a bank at the corner of Exeter. The third blast, which Ryan did not see but heard, happened near a firehouse at Hereford, the ladder street onto which runners turn from Commonwealth Ave. before they turn onto Boylston.
"My ears were ringing, my head's ringing," Ryan said. "Everyone was running like hell."