Maliciosa - Sierra de Madrid - Spain

The Sierra de Guadarrama is a mountain range forming the main eastern section of the Sistema Central, the system of mountain ranges at the centre of the Iberian Peninsula. It is located between the Sierra de Gredos in the province of Ávila, and Sierra de Ayllón in the province of Guadalajara. The range runs southwest - northeast, extending into the province of Madrid to the south, and towards the provinces of Ávila and Segovia to the north. The chain as a whole measures approximately 80 km in length, with its highest peak, Peñalara, reaching 2,428 m above sea level (7,965 ft).

This picture was taken from Navacerrada and represents a cloud above mount "Maliciosa" that really looks like an Atomic Mushroom...