Castells are human towers, which have been built for over 200 years in the Camp de Tarragona and the Penedès, and are considered a symbol of Catalan identity.
They have become increasingly popular first in Catalonia and now around the world since the 1980s and the number of colles or casteller groups increases by the year.
The colles are made up of hundreds of members and the basic structures are of one (pilar), two (torre), three, four and five although there are castells that consist of up to ten people at the base.
As far as the height is concerned, a very select group of colles have managed to build castells ten levels high and most of these have been built in recent years, when the so-called Golden Age at the end of the 19th century has been superceded.
Despite the physical preparation required, one of the most important developments in recent years has been the inclusion of an increasing number of women.
On November 10th 2010, Catalan Castells was made an Intangible Cultural Heritage by UNESCO.
During the season, there are a number of diades castelleres that for tradition, history and the level of the colles and the castells that are attempted. Here are some of the best ones.
June 24th, Sant Joan - Plaça del Blat de Valls
First Sunday after Sant Pere (June 29th) Festa Major - Raval de Montserrat de Terrassa
Sunday before Les Santes (July 27th) Diada de Les Santes in Festa Major de Mataró
Saturday before August 5th (La Mare de Déu de les Neus), Festa Major de Vilanova i la Geltrú
August 15th, La Mare de Déu d'Agost - La Bisbal del Penedès
Fourth weekend in August (Saturday) Festa Major - Plaça de la Vila del Catllar.
Fourth Sunday in August - Festa Major de L'Arboç and Festa Major d'Igualada
August 30th, Diada de Sant Fèlix - Plaça de la Vila in Vilafranca del Penedès
Closest Sunday in September before the Saints' Day of Santa Tecla (September 23rd) (First Diada is the First Sunday of Les Festes de Santa Tecla) - Plaça de la Font (Tarragona)
Closest Sunday in September to La Mercè (September 24th) - Plaça de Sant Jaume in Barcelona
September 23rd, Les Festes de Santa Tecla de Tarragona - Plaça de la Font in Tarragona
First weekend in October of even years - Plaça de braus in Tarragona (International Castell Competition)
First Sunday in October of odd years - Diada del Mercadal in Reus
Sunday closest to Santa Teresa (October 15th) - Diada de Santa Teresa in la Plaça Vella del Vendrell
First Sunday after Santa Úrsula (October 21st) - Diada de Santa Úrsula in la Plaça del Blat de Valls
Sunday closest to Sant Narcís (October 25th) - Diada de Sant Narcís in la Plaça del Vi de Girona
November 1st, Tots sants - Plaça de la vila in Vilafranca del Penedès
Third weekend in November, Diada of the Minyons de Terrassa - Raval de Montserrat in Terrassa