This is one of over 20 shelters built in Tortosa to protect the civil population from aerial bombings. Built under the slope of the Garrofer neighbourhood, air-raid shelter number 4 was paid for with public funds and was linked to another shelter at the end of Carrer Teodor Gonzàlez. It was the largest shelter in Tortosa, with a capacity for 400 people. It involves a system of galleries a metre wide and two metres high, dug into a ground of clay and rounded pebbles. It has a paved floor and brick and cement walls. A visit is highly recommended for those who want to get a feel for what it was like being in a shelter while bombs fell outside.