Castells or human towers are a spectacular tradition that is particular to Catalonia. Originally it was a rural cultural phenomenon, but urban mass holidays have lifted it to a new level of grandeur. The participants of such human towers are named Castellers. Visitors can watch weekly training sessions of Castellers de Barcelona Club from February to November to see how complicated and challenging the process is. Throughout the year, you might occasionally see the Castells in major celebrations such as La Mercè.