The deep waters that accommodate the container port also made Sines one of Portugal’s busiest fishing harbours in the middle ages.

This castle was put up to defend the fleet and town against enemy navies and pirates.

The hill it sits on has been settled since the Palaeolithic era, but the castle is only from the 15th-century.

That’s the reason the building is quite compact, as the streets around it had long been plotted when it was built and it had to adapt to that shape.

The keep is three storeys tall, and the handsome mullioned window at the top is original.

Not long after construction its warden was Estêvão da Gama, father of Vasco.