It still retains eleven towers, the most outstanding being the Torre de Menagem (Tower of the Keep), Torre do Haver ou do Tombo (Tower of Riches or Trumbling Tower), Torre do Paço (Tower of the Palace), Torre da Cisterna (Tower of the Cistern) and the Torre de São Lourenço (Tower of St. Lawrence) located on the hillside.
TOWER OF THE KEEP
This was the most important and robust tower of the castle, built to withstand heavy attack and therefore used as a privileged command post. The royal standard flag was hoisted here, as a symbol of the vassalage of the alcaíde (Moorish mayor) or governor to whom the king had entrusted the castle to hold and defend. The first geodesic observatory in Lisbon was set up in this tower in the 18th century.
TOWER OF RICHES OR TUMBLING TOWER
Because it contained the royal treasure (income from taxes and royal rents) it was called the Torre do Haver or Tower of Riches. As of King Fernando’s reign (1367-1383) it housed the Royal Archives and supposedly the most important documents of the kingdom would “tumble” or “tombar” into it. Hence the name, Torre do Tombo or “Tumbling” Tower, the name for Portugal’s main archive even today. Up until the earthquake of 1755, the Royal Archives were held in this tower, the Palace Tower and other buildings adjoining the castle that belonged to the Royal Palace. The Camera Obscura is a device that allows you to thoroughly explore the sights in Lisbon, and has been set on this tower since 1998.
Thus named because of its proximity to the former Royal Palace, to which it was probably connected. In the 15th century, during the reign of King Afonso V, the African, it adjoined a wing of the palace known as the “house of the lions” where two lions were kept. In the mid-16th century it also held the Royal Archives.
TOWER OF THE CISTERN
Thus named for its cistern used to collect and store rain water.
TOWER OF ST. LAWRENCE
Situated on the hillside, the tower was connected to the castle by a sheltered passageway — a feature characteristic of peninsular military architecture from the Moorish period. This guaranteed safe access to a well situated outside the castle (although wells were usually located at the base of a tower) or swift access to the exterior in case of siege, for escape or for reinforcements or supplies to come in.