In the late afternoon of 9/11, my brother and I ventured out from his apartment onto the deserted streets, to withdraw a chunk of cash from an ATM, in the event that we were about to enter a Mad Max-style futuristic dystopia. Anything seemed possible on that day, with the Pentagon under attack and an unknown number of passenger planes still unaccounted for. In one of the few moments of levity in the day – at least in retrospect – we carried tennis rackets with us to ward off looters. We strolled down the empty Upper West Side like Bizarro-world Williams sisters, alert and on the balls of our feet, ready for the apocalypse.