Rafael López Monne, photographer of heritage and hiking, described the valley of Cardó as "invisible mountains", concept that can be extrapolated to the whole massif, which deserves to be a natural park. Zona PEIN, maintains a structural unit with the Sierra de la Batalla and Els Ports and is integrated into the Catalan Pre-coastal Mountain Range. It is perfectly defined (12 km long by about 5 km wide). The northern relief is called Serra de Cardó and the southern Serra del Boix. We found the top in the Creu de Santos (941 m). The rock art stands out and is crossed by the GR-192 and the Vía Augusta. Fullola, Sallent, Costumà and Burgà are unsuccessful medieval repopulations.

Cardó contrasts with the Boix, the Coll de l'Alba and the Moles because the Carmelite monastery (1606) led to plant conservation. It highlights the yew of the shade of Cosp and the pines of the mas de Odres and the Coll de la Barca, the white goats and the eagles.
There is a gret interest in the Aumedielles, ravine of the Llet and the Creu (379 m), hermitages of Coll de l'Alba, Mig Camí, Sant Domingo and Sant Cristòfol (in ruins those of Cardó and el Carme). Medieval towers of Gassià and Fullola. Wind farm of the Baix Ebre. Refugio Font del Teix.