All of you certainly know a lake. Perhaps you have even been splashing around in a lake once because lakes are big stretches of water. But what actually is a lake? How did it form? What lives in a lake and around it? That is what we want to find out together. How do you actually recognise that you are at a lake? If you look closely, you see, simply put, that lakes are always where water collects in a very big depression on the earth’s surface. Contrary to rivers, lakes are therefore bodies of water that are surrounded on all sides by a shore.