The qraqeb are made of two pieces of curved iron clicked together with one hand. A whole row of musicians playing them at once sounds like a galloping horse. They are easy to start but very hard to master - the best players can do impossibly fast patterns without tiring.
The guembri is a beautiful instrument. It has only three strings, a wooden box covered with camel skin, and a deep boomy sound - much lower than a guitar. The player plucks bass notes with one hand while clapping the wood for rhythm with the other.
Gnawa music can go on for hours. The musicians wear long colourful robes and tall hats with cowrie shells sewn onto them. Tassels swing as they dance. The music is meant to send the listener into a kind of dreamy, peaceful state.
Every June, the seaside city of Essaouira hosts a giant Gnawa festival. Musicians from Morocco and all over the world come to play together. Hundreds of thousands of people fill the streets to listen, dance and clap along.