Peace in the Mountians
The San Lorenzo de El Escorial Monastery just outside of Madrid is one of the best things to see on a day trip from the capital. The monastery is set on the edge of the mountains in an atmosphere of oak groves, rolling hills, gardens, and ponds and a stroll through the geometrically-manicured gardens with the snowy mountains in the background is a very welcome chance to disconnect from the graffiti-riddled chaos of Madrid.
The interior of the monastery is spectacular and has some frescoes and painted cupolas to rival anything found in Rome (my wife swears it's better than the Sistine Chapel).