The M-501 west of Madrid has a reputation. Known to everyone as the carretera de los pantanos, the road of the reservoirs, it runs from the edge of the city towards the Sierra de Gredos past a string of lakes, and on weekends it fills with motorcycles heading for the mountains. This finish lies at its eastern end, near Boadilla del Monte, where the capital's wealthy suburbs meet the pine and holm oak of the Monte de Boadilla.
Boadilla has one grand building. The Palacio del Infante Don Luis was built in the eighteenth century by Ventura Rodríguez for the brother of King Charles III, who lived here with his court of musicians and artists, including the composer Luigi Boccherini. The palace has been restored and its gardens are open to the public.
The forest around Boadilla is a remnant of the Mediterranean woodland that once covered the area, and it is home to deer, rabbits and birds of prey. Walking and cycling paths criss-cross it, and it is a pleasant place to stretch out after a long ride.
Coming back from the Alto Tajo, the final stretch is a dash along the motorways around Madrid, the M-40 and M-50, with heavy traffic and speed cameras. The M-501 itself is closely watched by traffic police and cameras, a consequence of its accident record.
Supplies are a non-issue in these suburbs. What matters is the timing: Madrid eats late, so if you roll in at eight the bars around Boadilla's old centre will only just be warming up. A caña and a plate of jamón at the counter will hold you until dinner.