Whilst walking the Camino Sanabres (link) in 2017 we passed through Laza, a small town with a population of 1200 about an hour’s drive south-east of Ourense in southern Galicia (NW Spain). Here we learnt of the strange Carnival, claimed by locals the be the world’s oldest and original. Men dressed in strange costumes (Peliqueiros) prance in the streets on Sunday morning carrying whips to hit bystanders as a reminder that it is time to play. 

Monday is the “dirty” and “wild” day of Laza’s Carnival – an all-out mud war lasting more than two hours. A few young men go into the countryside collect ant-filled dirt and then run into the plaza flinging dirt and ants into the air and on to the spectators.

In nearby Xinzo de Limia the characters represent the religious, judicial and social powers and are responsible for ensuring that no one is allowed to stroll undisguised. Their law is absolute; anyone who dares to walk without costume is marched to the nearest bar and ordered to buy wine for all.

We really wanted to see this so in 2020 we are back.
There is more information here (in Spanish). For an English translation click here.