It started out on the bridge but got released before it had enough heat inside to take it aloft. It drifted elegantly down to the river, to become part of the massive amount of debris which was pumped into it over the course of the night. Did you know that fireworks continue to burn briefly underwater? I saw many rockets get misdirected into the water, and a stream of smoke (not just steam) seemed to exit the water along the direction it was travelling. (Steam isn't as dark as smoke, that's why I think it was smoke.)