If nature, tranquillity, and hiking sound tempting, you need to go to Rascafría. There is a hiking trail called Cotos Forest. Its length is about 8.5 km. The route is assessed as difficult, as it will take you through a range of obstacles. As a bonus, you will get crystal waters of natural pools among green meadows.
The water temperature in them justifies their name, really cold and invigorating, but in the sultry July–August, it can be a true gift. The capital's inhabitants love this picturesque place, located in Valle del Paular.
The best time for trekking in Cotos Forest is from March to November. Take a train from Madrid to Cercedilla, and then another one to Cotos.