Situated on the left Mondego river bank, the Paúl de Arzila Natural Reserve occupies an area of about 535 hectares.
This is one of the richest marchlands in Portugal, with an important Flora with about 300 species, and a rich fauna that counts about 119 birds species, 14 mammal species, 10 different reptiles species and 13 fish species, many of them in risk of extinction, finding here a place of peace and protection, like the red heron, which is also the symbol of the Reserve.

This Nature Reserve also provides an Interpretation Centre, with several temporary exhibitions and varied information and promotion material, as well as pedestrian itineraries suggestions.
From the balcony of this centre one has a wonderful panorama over the marshland, being able to recognize some of the many different species that inhabit this territory.
The Reserve also provides an observatory to a better understanding and knowledge of the richness of this area, and also offers to its visitors a Park for picnics and other facilities.