Will the Seine be clean enough to swim in by the Olympics? Not even the experts know

Triathlon and marathon swimming are to take place in the Seine, where it has been illegal to swim for more than a century. The water has tested unsafe in recent weeks, and cleaner on other days.

Triathlon and marathon swimming are to take place in the Seine, where it has been illegal to swim for more than a century. The water has tested unsafe in recent weeks, and cleaner on other days.

(Image credit: Michel Euler)