The Peña del Yelmo (Rock of the Helmet), or Peña del Diezmo (Rock of the Tithe), is the most symbolic granite peak of La Pedriza del Manzanares. Its aspect of helmet over the formations eroded of La Pedriza makes it the most identifiable top in spite of it isn't the highest peak of the area. The easiest route to the summit is in their north face, although it have a lot of routes of rock-climb in its south face of several difficulties. Here's the school of rock-climb.
The first climb was by Casiano del Prado in 1864.
For more information about La Pedriza and the park of Cuenca Alta del Manzanares you must visit the web of the range: La Pedriza.
-North face: the narrow gap in the North face is the easiest access (II, P.D. inf). Because it's a small chimney, and it's not exposed, many people without experience in rock-climbing can reach the summit.
-South-West ridge: route Valentina.
-South face: all the routes are rock-climbing. Some routes about IV: Vikinga, Higinios, Clavera… Some routes about V: Guirles-Campos, Nani, Gálvez-Pascual…
The best trailhead is Canto Cochino (1.025 m) in the natural park but it's possible the ascent as well from the village of Manzanares el Real ( 908 m ), with trailhead in El Tranco (960 m) at N.W. of the village.
-From Canto Cochino: the path to Pradera del Yelmo across senda de las carboneras is the shortest and easiest to follow but another options goes across the labyrinth of Hueco de las Hoces (a long ravine with a lot of plants and rocks) or the refugio Ginés de los Ríos ( 1195 m ) across col de la Vistilla (longest but interesting).
-From El Tranco: we'll connect with the same path of carboneras to Pradera del Yelmo.
Manzanares el Real is the nearest village. From Madrid you must take direction to Colmenar Viejo and Tres cantos across M-607, M-609, M-682 and M-608. From Manzanares el Real you follow 1 km to S.W. to reach the fence of entry of La Pedriza, driving 12 km to the parking of Canto Cochino.
La Pedriza is a natural reserve with rules about the wildlife conservation.
It's very advisable the approach early in the morning to Canto Cochino in week-end because if the parking is full you must wait in the fence (generally in midday a lot of people from Madrid goes to La Pedriza to lunch in the natural area).