The castle is in the north-western outskirts of the city and the hill where it was built is now a pleasant park for walks and relaxing views of Cagliari's skyline, even though it's surrounded by blocks of flats. It dates back to the 14th century and it was needed by the Aragonese conquerors to consolidate their power and to prevent attempts of invasion from the north. Despite the many transformations made to it over the centuries, the castle has preserved its three mighty towers and a deep moat around it. St Michael Castle is used as a venue for temporary exhibitions and other events.