Dogs, dinosaurs, elephants and people - all could use a dip to cool down when the thermometer rises.
Swiss rivers are a magnet in summer. Clean water and natural beauty make splashing in them a pleasure but this was not always the case. Until the 1950s Switzerland's water bodies were repositories for waste water and sewage. There is still some work to be done. By 2040 micro-impurities from medicines and other chemicals will be filtered out in water treatment plants.
The large number of recreational users pose problems of their own. A viral video describing the village Lavertezzo in the Ticino Verzasca Valley as the "Maldives of Milan" resulted in a flood of visitors from Italy. The authorities struggled to cope with the traffic and litter.