A third of the world watched live as the World Trade Center collapsed on September 11, 2001; a third more heard about it within 24 hours. (Do you remember where you were?) So exhibits at the soon-to-open 9/11 Memorial Museum will reflect the diversity of the world's experiences of that day. In a moving talk, designer Jake Barton gives a peek at some of those installations, as well as several other projects that aim to make the observer an active participant in the exhibit.