 Although participants do not need to be deeply religious or regular churchgoers, it is desirable for them to have an active interest in the sources and expressions of religious faith, particularly as displayed in the buildings of the great Christian churches of Europe.ARC UK is a branch of the network of ARC organisations which exist in Belgium, France, Germany, Italy, the Netherlands and Spain.ARC currently facilitates over twenty projects, including St. Paul's Cathedral in London, the Duomo in Florence, Toledo Cathedral, Christ Church Cathedral in Oxford, Westminster Abbey, Reims Cathedral, the Dom in Erfurt and the Basilica di San Marco in Venice.