Members of the Castellers de Vilafranca colla complete their human tower during the 24th annual Tarragona Castells competition. The 'Castellers' who build the human towers compete in groups, known as 'colles', at local festivals in the hope of erecting the highest and most complex human tower. The Catalan tradition is believed to have originated from human pyramids built at the end of the 18th century by dance groups

Photograph: David Ramos/Getty Images