The recent floods are forcing the lakes to give up their grisly secrets.
Over the weekend two bodies were found in Lake Constance – both had been dead for several months at least.
Police say it’s likely the floods have churned the water, bringing the bodies close to the surface.
While they have not been formally identified, there are records of many missing people thought to be in the lake.
A paddle boarder went missing last August and two fishermen were caught in storm in 2012 – and only their boat was recovered.
In all there are 100 cases known to police in Switzerland, Austria and Germany – the three countries the lake borders.
But some will stay hidden. An Austrian police officer explained if the body is more than 50 meters deep – the water pressure will keep it below the surface.