Ancient cultures were accustomed to celebrating the end of Autumn by making fires. It was an opportunity to bring the community together during the longest night of the year and I think that Christians have never changed the tradition an they just called it San Antón instead.
In Almería, my hometown, it is a very popular tradition. It seems that San Agustín holds the biggest fire in Spain. This small town in El Ejido doubles its size every year so it is not a surprise that the festival is getting bigger and bigger.
The day starts by collecting wood from the greenhouses and farms nearby. Then, when dusk is over locals burn the wood to make barbecues. The most exciting point comes at the end of the night when people jumps over the coals. They then listen to music or dance the night away until the next day.