Atalburu is a Basque word that means "headwaters." This refers to the source of a river or stream, like where the water first starts to flow. Imagine a huge drinking straw that goes all the way down into the ground and sucks up water from deep inside. That water then starts to flow out in a tiny little stream, which gets bigger and bigger as it flows downhill. The very beginning of that stream is the atalburu, or headwaters. It's important to take care of the atalburu because if something bad happens there, it can affect the entire river or stream downstream. For example, if there's pollution or something toxic at the atalburu, it will end up in the water that people and animals drink later on. So, keeping the atalburu clean and healthy is really important for everyone who uses the water downstream.