Zäuerli is a type of singing that comes from Switzerland. It's really special because it's all about making music with your voice, without using any instruments.
When people sing zäuerli, they make sounds that are kind of like whistles and yodels mixed together. They might start with a high pitch and then let it slide down to a lower pitch, or they might switch back and forth between two different notes really fast.
Zäuerli is often performed in the Swiss Alps, where the mountains help to make the singing sound even more beautiful. People have been singing zäuerli for hundreds of years and it's still really popular today. So if you ever find yourself in Switzerland, be sure to listen out for some amazing zäuerli singing!