Originally constructed between 1553 and 1570, the aqueduct stretches 45 kilometres (28 mi) long, beginning at Tecajete volcano just east of Zempoala and terminating at Otumba.[1] It passed mostly at ground level, but also went underground as well as over ravines and valleys. There are three arcades along the aqueduct: the first has 46 arches, the second has 13, and the third has 67 arches. The highest valley the aqueduct spans is Papalote ravine, which is crossed by the 67 arch arcade also known as the Main Arcade, with the tallest arch standing 38.75 metres (127.1 ft)