The town of 55,000 inhabitants nestles on a steep rock promontory between the rivers Eresma and Clamores. The top of the cliff does not provide much space for the historic town, which is a labyrinth of narrow streets, picturesque market squares, and proud Gothic churches. The center is marked by a mighty castle, the Alcázar, rising up and providing magnificent views of the plane and the Sierra de Guadarrama. Together with Toledo and Avila, Segovia used to be one of the most important cities of the historic region of Castile. In 1985 the medieval city of Segovia and its Roman Aqueduct were declared World Heritage by UNESCO.