The exhibition shows the importance of the quality of the water in the gorges of the Areuse. They have been supplying water to two-thirds of the population of the canton of Neuchâtel for more than a century. The exhibition highlights the tiny shellfish Gelyella monardi, less than 1/3 of a millimetre in size. This unique animal has been inhabiting the vast (under) water reservoirs for 20 million years. It is a bio-indicator of water quality and is internationally recognised as a unique animal.