Following Bailén Street past the Royal Palace and Viaduct, you arrive at Las Vistillas Viewpoint, where you can contemplate the unbeatable views of the Almudena Cathedral, Casa de Campo, and, on clear days, the Sierra de Guadarrama mountains, which were the Christian-Moorish front during the Moorish Invasion. Las Vistillas was used as a look-out during those days to keep track of the advancing Moorish troops.