On this damp day (back in October), no one was interested in swimming in the East Bank Club's rooftop pools (500 North Kingsbury). And no one in their right mind would think about swimming in the North Branch of the Chicago River just next door. But the Hudson River is now clean enough for people to swim around Manhattan. Maybe in our lifetimes, we'll see a beach in downtown Chicago like the one in Paris. Maybe at Wolf Point? I wonder what it would take to make that happen.