Celtics fans cheered and sang “Sweet Caroline,” a Neil Diamond song traditionally sung at Boston Red Sox games at their home stadium, during the NBA championship parade in Boston on Friday, June 21.Video captured by Keegan Caldwell shows fans gamely belting out the song while celebrating during the parade, which was expected to draw over one million people to Boston.Players were paraded through the route on duck boats, as massive crowds of people packed the streets to watch, according to local reports. Credit: Keegan Caldwell via Storyful