The fortress of St. George since ancient times has been the strengthening of guarding the Tagus estuary. In 1147 king Alfonso Henriques converted the fortress into a Royal residence. In 1511, king Manuel I built a Palace outside the fortress, and here placed an Armory and a prison. In the earthquake of 1755, the fortress was badly damaged and only in 1938 began restoration work, but little remains of the former buildings.

Walls have been restored and you can now stroll around the old quarter of Santa Cruz. In fortress towers arranged various exhibitions depicting the history of the fortress and the city. With observation decks offer a magnificent view over Lisbon.