Before revision: History Work on the secret underground complex started in 1940, during the siege of Malta, when a series of tunnels under the Upper Barrakka Gardens and the Saluting Battery that had been used as slave quarters during the Hospitaller period began to be expanded.
After revision: History The British started work on the secret underground in 1940, during the siege of Malta, when a series of tunnels under the Upper Barrakka Gardens and the Saluting Battery that had been used as slave quarters during the Hospitaller period began to be expanded.