The complete back issues of this magazine—all 1,680 of them—are stored in a walk-in closet in our New York offices. We don't often visit the place. It's musty and locked, and only one person keeps a key. But to put together our May issue on the Future of Flight, which arrives the same month that Edward L. Youmans founded Popular Science Monthly in 1872, we spent many hours there. During our sojourn, things took a turn for the strange.