The only fortified entrance remained in Stampace district, that of ‘Portu Scalas’, is the oldest among the Pisan towers of Cagliari. It was built in 1293, a decade before the construction of the other towers in Castello district.

The tower, with a quadrangular map and about 20metres high, named also ‘dello Sperone’, has a loophole to testify the ancient defensive function.

It has become, over the centuries, part of San Michele Military Hospital; however, it still represent the entrance to the high part of Stampace.