The region north of Madrid, into some parts of Ávila and Segovia, is taken up by the Sierra de Guadarrama mountain range, which became Spain's 14th national park in the summer of 2013. Long favored by naturalists, writers (including John Dos Passos), painters, poets, and historians, it also attracts sporty madrileños looking to get away from the chaos of the capital. The Sierra's eastern border lies at Puerto de Somosierra, west of the A1 highway heading to Burgos; the little town of Robledo de Chavela, southwest of El Escorial, marks the park's western edge. Near the middle of this long stretch sprouts another branch to the northeast, giving the Sierra de Guadarrama the shape of a fork, with the Valle de Lozoya in its tines. Hiking options are nearly limitless, but two destinations stand out for their geological importance: the Parque de la Pedriza, a massive, orangey, fancifully shaped granite landscape in the Cuenca Alta del Manzanares, and the Peñalara's alpine cirques (basins) and lakes.
Arawak Viajes Madrid. This travel agency offers three or four different day trips every weekend to different spots in the Madrid Sierra (and to Guadalajara or Sierra de Gredos), plus a weekend trek every month. Prices to the Sierra de Guadarrama are usually around €20–€26. You must reserve in advance and pay within one day of making the reservation. Buses depart from Estación de Autobuses Ruiz on Ronda de Atocha 12. Calle Ercilla 28, Embajadores, Madrid, 28005. 91/474–2524; www.arawakviajes.com.