I had left my bike unlocked in the back of my building. In retrospect I clearly shouldn't have, but the building wasn't visible at all from the street, was very quiet, and was also behind a locked fence (although it wasn't hard for someone to jump a much shorter fence to get to the bike, which is probably what happened.) Someone would have had to have already known that a bike was left there unlocked for them to get it. My theory is that a high schooler took the bike -- another bike, a much smaller Trek, was left behind, with the name Leo Higgins engraved onto it. Pretty crushed about losing this bike, I've had it for more than four years and have ridden it everywhere.