Central System

The western ranges of the Central System divide the basins of the Duero and the Tagus. Among them rises the Sierra de Gredos, a high granite barrier crowned by Pico Almanzor. Ancient glaciers carved deep valleys and broad cirques into its northern slopes, leaving lakes and ridges of moraine among the peaks. Mountain passes such as the Puerto del Pico provided routes between the Castilian plateau and the warmer valleys to the south.