Park of los Cerros Nature · Alcalá de Henares, Cuenca del Henares, Madrid A public-utility forest (Spain's forest-protection designation) since the year 2000, it protects some 806 hectares of gypsum hills and moorland southeast of the Henares, with pine groves, holm oaks and rosemary scrub crossed by four marked trails of between 2.5 and 10 kilometres. Composed mainly of clay and gypsum, they rise with very steep slopes to flat summits reaching 843 metres, marking the boundary between the Alcarria and the Campiña de Alcalá. Because they were easy to defend, they were home to the pre-Roman oppidum and the Andalusi fortress of Alcalá la Vieja, while the Roman city of Complutum settled in the plain below. Among its heights stands out the Cerro Malvecino, scene of the Christian siege of 1118 against the Muslim fortress, and Monte Gurugú, which took its name from a battle of the war in Africa. Photo: Raimundo Pastor (CC BY-SA 4.0) What to see and do in Alcalá de Henares