They say that fire drives out evil spirits, that it purifies, protects and regenerates. On the night of Sant Joan, fogueres, or bonfires, are lit when the sun goes down and kept going well into the night or early hours of the morning, with all kinds of junk that burns. Attracted by the fire's magnetism, people gather round, sing and dance, while the most daring among them jump or tread over the embers. In the past there was a lot of competition between bonfires and rivalry often developed between groups who pinched wood off each other to make the biggest one.

The relationship between the summer solstice and fire goes back a very long way. We know that the earliest Mediterranean civilisations celebrated the shortest night of the year by lighting fires. Over the course of history this ritual has survived in different circumstances: it was adopted by Christians at the end of the Roman Empire, carried on thanks to the cultural permissiveness of the Arabs and, in harder times, it survived because of its roots in the family environment. In reality, the fire tradition is maintained thanks to its implicit social, collective and ceremonial character.

A variation on the Sant Joan fogueres are the falles, logs that, in some Pyrenean villages, are carried lit across the shoulder or rolled down the mountain to the square, where they are piled up to form fogueres.

The use of fireworks is one of the spin-offs from the fire ritual: on Sant Joan night various fireworks light up and explode, including flares, bangers, airbombs, firecrackers, conic fountains, rockets, catherine wheels, snaps and screamers, which all add light and noise to the festival. Remember the saying: "Qui encén foc per Sant Joan no es crema en tot l'any". (Whoever lights a Sant Joan fire will not burn throughout the year.)