There was time when people were not afraid of bathing in the Moscow river. The water was clear enough and people were less demanding than today. 50-70 years ago they didn't think much about ecology or treatment plants, they polluted the river and it was considered to be normal. Boys swimming opposite the Kremlin were not uncommon. It was a good time. If they had a beach near the Kremlin today, would you plunge?
In 1910 even horses bathed in the river.