In the Valle de las Navas, known as the Arizona burgalesa, is located a territory in which a steppe-like character of fanciful appearance and varied tonalities predominates. Modelled by erosion in the soft Tertiary and Quaternary materials, the area is made up of calcareous conglomerates, red clays, yellowish sandstones, white and grey loams, limestone and sand from the Lower Miocene. This Burgos desert, which is not so deserted as it is the ideal habitat for many species of steppe birds and birds of prey such as the golden eagle, has its main access from Tobes and Rahedo.