Episode notes
The Aqueduct of Segovia in Spain rises 28.5 meters over the Plaza del Azoguejo on 167 arches of granite blocks stacked without mortar, and it supplied the city with water until 1973. Its dedication inscription wore away, but Géza Alföldy reconstructed it from the anchor holes of its lost bronze letters, crediting Domitian and proposing completion in 98 AD. Evidence found in 2016 instead points to a start after 112 AD, under Trajan or early Hadrian. The water begins 17 kilometers away at the Río Frío, passes a gathering tank called El Caserón and a decanting tower called the Casa de Aguas, then runs 728 meters at a steady one percent grade to the Postigo.
Ashlar masonry lets the weight of the blocks lock the arches in compression, and the pillars taper from about 2.4 by 3 meters at the base to 1.8 by 2.5 meters on the upper tier, all to carry a channel only 0.55 meters wide. In 1072 an attack by the Moors destroyed 36 arches, a gap that lasted almost four centuries until Ferdinand and Isabella had Prior Pedro Mesa of the Jerónimos del Parral monastery rebuild them in matching Roman style. Leaks and pollution driven decay of the granite put the aqueduct on the World Monuments Watch in 2006, leading to traffic bans and a conservation effort.
- The chorobates, a 20 foot water filled leveling bench used to survey the grade
- The Arevaci, the Celtic people who lived in the area before Roman troops settled
- A statue of the Virgin Mary replacing Hercules, the city's legendary founder, in an upper niche
- Cadets from the military academy climbing the aqueduct every December 4 for Saint Barbara's feast
- The aqueduct as the mint mark on coins struck at the Real Casa de Moneda, powered by the Eresma River