Maxwell 1995, p. 24 The Águas Livres Aqueduct (Aquaducto das Águas Livres), built by order of John V and put into service in 1748, was so well constructed that it was unharmed by the earthquake of 1755; it had 127 masonry arches, the highest of which is in the stretch crossing the Alcântara valley, and is 65 meters high.