A mariachi band usually has between four and twelve players. They dress in matching outfits called charro suits - silver-buttoned jackets, tall hats and embroidered trousers. Some of the outfits are over 100 years old in design and look as polished as a circus ringmaster's.
The two instruments you won't have seen anywhere else are the vihuela and the guitarrón. The vihuela is a small, round-backed guitar with five strings that sounds bright and quick. The guitarrón is huge - it looks like a guitar that's swallowed a beach ball - and plays the deep bass notes.
Mariachi songs are mostly about everyday things: love, family, friends, the village you grew up in, the sun, a horse, a long journey home. People sing along loudly. The audience often shouts a happy yell called a 'grito' in the gaps between verses.
Mariachi was born in the western state of Jalisco around 150 years ago. UNESCO now lists mariachi as part of the world's cultural heritage - meaning it belongs to everyone. You'll hear mariachi at Mexican weddings, birthdays, festivals and Día de los Muertos celebrations.