Queen Elizabeth II, who was in Menorca, visited La Mola on September 18, 1860. Her Majesty was accompanied by the Ministers of War, Navy and Development, as well as foreign diplomats and various generals.
Colonel Romero, head of the works, accompanied the Kings on their visit to each of the constructions that were being carried out.
Isabel II was very satisfied and, because of that, she granted Colonel Romero the charge of Carlos III. As a consequence of said visit by the Queen, the work in the fortress was increased with the reinforcement of two companies of workers of the Corps of Engineers, thus reaching the number of 3,000 workers.
The construction process of the Fortress of Isabel II was very long, so that on September 15, 1876, the total invested in the works reached the figure of 8,690,000 euros.