Cercedilla is one of the spots that's most frequented by Madrid residents in the summer. In the Fuenfría Valley you'll find these pools located along the Arroyo de la Venta river. They were created in 1978 and, although the water is now chlorinated, they started out as completely natural swimming holes. The Las Berceas recreational complex also has a snack bar, lawn areas, bathrooms, changing rooms and a sickroom. It's open from 10am to 8pm until the end of August from, and admission costs €6 on weekdays and €7 on Saturdays, Sundays and holidays. Children under 14 and adults over 65 pay €4.