Second largest fort   When it was completed in 1774, La Cabaña was the second-largest colonial military installation in the New World. Over the next two hundred years the fortress served as a base for both Spain and later independent Cuba and also served as a prison by the government of Fidel and then Raul Castro. The complex is now part of a historical park, along with the El Morro fortress, and houses several museums. Every night a cannon is fired at 9pm, "El Cañonazo de las 9", a custom kept from colonial times signaling the closure of the gates in the city wall.