St George's Fortress has been a fortification protecting the Tagus estuary since ancient times. In 1147, King Alfonso Henriques converted the fortress into a royal residence. In 1511, King Manuel I built a palace outside the fortress and used it as a weapons storehouse and prison. In the earthquake of 1755 the fortress was very badly damaged and it was not until 1938 that restoration work began, but little remains of the former buildings.
The fortress walls have been rebuilt and it is now possible to walk along them around the ancient neighbourhood of Santa Cruz. In the fortress towers there are various exhibitions about the history of the fortress and the city. The observation decks offer a magnificent view of Lisbon.
