My phone has a "panorama" mode, but the software cannot seem to handle such a complicated scene as well as I had hoped. Nevertheless, this photo (click on it to see it full screen) gives you the impression of what it looks like to have so many Jews together at once.
And while a quick glance at the image seems to show mostly, yeshiva/"black hat" and Chassidic Jews, in fact all types were there. For example, at the end of the "official" singing to celebrate the Siyum, a group of "kipa sruga" Israelis kept singing for another five minutes, much to the consternation of the organizers.Virtually every speaker stressed the idea of Jewish unity at this event organized by the right-wing Agudath Israel of America.
Rabbi Yitzchok Alderstein writes a very nice op-ed about the phenomenon at the Los Angeles Times. The New York Times, in contrast, spends more than half of its own Daf Yomi coverage on how women are discouraged from studying Talmud in right-wing circles.