The Aqueduct of Segovia marches across the Plaza del Azoguejo on two tiers of arches, rising 28 metres at its tallest point, and it is one of the best-preserved Roman structures anywhere in Europe. Built around the first century AD under the emperor Domitian or Trajan, it supplied the city with water from springs in the Sierra de Guadarrama for almost two millennia. Standing beneath it and looking up at the precision-cut granite blocks stacked without mortar is a genuinely affecting experience.
The aqueduct forms the eastern gateway to the old city and is most dramatic when approached from the lower town. The best viewing point is from the square below, but you can also walk up to the raised walkway on the city wall level for a different perspective. Photography is best in the early morning before the tour groups arrive; in the afternoon it sits in the sun and the golden stone glows.