Parisians got a brief taste of swimming in the Seine—a historic first in 100 years—before heavy rain spoiled the fun. Officials had just lifted the century-old ban, but pollution concerns forced them to close the river again almost immediately. Turns out, old habits (and pollution problems) die hard.

Editor’s Note: This isn’t just about a quick flip-flop on swimming rules—it’s a stark reminder of how hard it is to clean up urban waterways, even with big promises (like Paris’s Olympic swimming plans). If a major city can’t keep its iconic river safe for a dip after heavy rain, it raises bigger questions about our fight against pollution.