The chestnut tree of Cotanillo is on the first terrace of the ravine, marked with the milestone of the inventory of singular trees of the Community of Madrid, which includes 283 living beings from the forest kingdom, among them the longest-lived tree on the Iberian Peninsula, a yew of thousand three hundred years living in the municipality of Rascafría. The chestnut tree of Cotanillo is 26 meters high and 320 years old, a venerable and ancient vegetable character of the Madrid mountains. In 2015 it has undergone a notable pruning to remove dead branches and damaged by age but it remains a respectable and admired giant in the valuable chestnut groves of Zarzalejo. To follow the route, you have to leave the valley where the old chestnut tree lives to the west, climb the small hillside to a copse of pines and go down to a gate on a rural road that descends towards the town.