The design of the work Plan Caval was changed several times. When it was finally approved the budgets were limited which slowed down the construction even more. When the war in the Alps broke out in June 1940 it was not finished at all. Only three blocks were ready for action, but the galleries were still under construction. Nowadays the tree trunks used during the construction work still survive, but the galleries have collapsed at several points. This makes the visit of the work very risky.