Human Towers are very popular in the province of Catalonia. While I was in Barcelona, I lived in a family-oriented area called Gràcia. Every second Sunday, the people of Gràcia would gather to witness the building of a castell. The goal is to assemble and dissemble a tower without falling. Usually, a small child is sent to the top of the tower and raises four fingers to represent the flag of Catalonia. The castell originated at the end of the eighteenth century in the city of Valls, near the city of Tarragona.