The sturdy walls of Dalt Vila were designed by the Italian engineer Giovanni Battista Calvi, who was in the service of King Philip II at the time. Its construction was a grand work initiated in 1555 which conserves the original layout, characterised by the presence of seven bastions. Today, the casemate – a half-covered courtyard where the artillery was kept – of the bastion of Sant Pere has become a space that illustrates the complex construction of the walls, through audiovisual elements. And the bastion of Sant Jaume, too, has been turned into a museum on military technology that shows the evolution of the fortifications and pyro-ballistics.