Looking out from Castro Marim castle you see the sea on one side and on the other the rounded shapes of hills stretching away to the horizon. These are the uplands of the interior and they issue a silent challenge to everyone who is at home in wide, open spaces, who takes pleasure in bird watching or likes to walk or cycle, who appreciates the bounty of the natural world.

Linking the church, the castle and the fort, the streets of Castro Marim are lined with houses whose simplicity is typical of the architecture of the Algarve. White predominates, broken here and there by ochre and luminous blues. The bright borders painted on the facades bespeak a taste for geometrical patterns and floral motifs.

Covering an area of 2,089 hectares, with wet areas of salt marsh, salt pans and creeks and dry areas of schist soils, red clay, arenite and sand, the reserve contains a wide variety of biotopes. It therefore offers a unique opportunity to observe the different ways in which plants and animals adapt to the natural environment. For most visitors, the reserve's biggest attraction is undoubtedly the large number of birds - especially aquatic birds - that can be seen there. There are 153 species to spot, including storks, avocets, sand pipers, mallards and the ever popular flamingos.