Heritage Open Day: A testimony of civilian resistance, silenced during Franco’s dictatorship, the network of underground air-raid shelters still lives under the streets of Barcelona. Explore this exhibition at Ramsgate Tunnels. An extraordinary testimony of civilian resistance, forcibly silenced for decades during Franco’s dictatorship, the network of 1,322 underground air-raid shelters still lives under the streets of Barcelona. The model of Catalan shelters, a new and revolutionary way of civil protection built by local communities, was at the centre of the debate on the defence from air raids in the UK. It is not only a building technique but also a mirror of society.