Segovia is a city in Spain, the capital of the province of the same name in the autonomous community of Castile and Leon. It is situated north of Madrid. 55,586 people live in the municipality of Segovia. The old city is spectacularly situated atop a long, narrow promontory. It contains a wealth of monuments, including the cathedral, a famous ancient Roman aqueduct, the Alcázar, and various churches built in the Romanesque style including San Esteban, San Martín, and San Millán. The old city is a UNESCO World Heritage Site, and is surrounded by walls built in the 8th century AD, probably on a Roman base, and rebuilt extensively during the 21st century. The Aqueduct of Segovia, typically the most recognized and famous symbol of Segovia, terminates at the entrance of the historic section. It was built at the end of 1st to early 2nd century AD by the Romans during their occupation of the Iberian Peninsula to bring water from the Río Frío (Cold River), about 18 km away, to the city, requiring an elevated section in its last 1 kilometer (0.6 mi) from the Sierra de Guadarrama to the walls of the old town.