Old Town of Segovia and its Aqueduct

The aqueduct of Segovia is part of a Roman water supply that brought water from the Río Frío in the mountains 17 km away. UNESCO gives the structure a length of 813 m, with two tiers of arches on 128 pillars rising 28.5 m at the lowest point of the valley, and its granite blocks are laid without mortar. Its inscription has lost its bronze letters, so the date is uncertain: in the late 20th century Géza Alföldy deciphered the text from the anchors that held the letters and concluded that Domitian ordered the work, but evidence published in 2016 points to a date after AD 112.

Thirty-six arches destroyed by the Moors in 1072 were rebuilt in the reign of the Catholic Monarchs under Pedro Mesa, prior of the nearby monastery of El Parral, with care not to change the original style, and the aqueduct supplied the town until 1973. At the western end of the old town stands the Alcázar, begun around the 11th century. When news of Henry IV's death reached Segovia on 12 December 1474, Isabella took refuge in the Alcázar, and the next day she was proclaimed Queen of Castile in the town's main square.

The old cathedral stood beside the Alcázar and was left in ruins after a siege during the Revolt of the Comuneros, which broke out in 1520. Charles V ordered a new cathedral on a different site, and its first stone was laid on 8 June 1525 to designs by Juan Gil de Hontañón. UNESCO describes it as the last Gothic cathedral built in Spain, and the old town and its aqueduct were inscribed as a World Heritage site in 1985.