The biggest of the city festivasl- La Mercè – is happening every year in september. It is a colorful cultural mix of catalan traditions with masks, monsters and the fire walkers (Correfocs). More highlights are the Castellers and Giants. At the last day you can see gigantic fireworks with music at Placa Espanya. Usually the same time the BAM festival (Barcelona Accio Musical) is held, which also contributes with lots of stages and international artists to the Mercè. A spectacle for 3 days, which you should not miss if you are in the city.