Photos of a Million People Taking Part in a Little Known Christian Tradition

This article originally appeared on VICE Spain.

El Camino del Rocío is one of the most famous pilgrimages in Spain, attracting almost a million Christians to the southern region of Andalusia to mark the holy day of Pentecost.

The procession, which can take up to a week, is organised into dozens of brotherhoods, travelling along the roads of the village of Rocío. Some people walk it, while others ride on horseback or in carts pulled by donkeys or cows.

The parade is extremely colourful and loud, with pilgrims in bright flamenco tunics and hats singing traditional songs. At night, they camp out in the open air around a fire, sharing food and wine, and partying until the early hours.

Some pilgrims can take up to a year to prepare for the festivities, and are particularly meticulous when it comes to decorating their carriages. Photographer Mathieu Richer was at this year’s El Rocío pilgrimage to capture the event.

Scroll down to see more of Mathieu Richer photos.