Roman aqueduct
Rome's first aqueduct was built in 312 BC, and supplied a water fountain at the city's cattle market. By the 3rd century AD, the city had eleven aqueducts, sustaining a population of over a million in a water-extravagant economy; most of the water supplied the city's many public baths. Cities and towns throughout the Roman Empire emulated this model, and funded aqueducts as objects of public interest and civic pride, "an expensive yet necessary luxury to which all could, and did, aspire".
Jerusalem during the Second Temple Period
The aqueduct, a method of conveying water to the city, was an integral part of Roman city planning. Already quite large, Jerusalem needed to satisfy the needs of countless pilgrims annually, requiring much more water than was available. Water was taken from Ein Eitam and Solomon's Pools, about 20 kilometers south of Jerusalem crow flies and about 30 meters higher in altitude than the Temple Mount. Like its Hasmonean predecessor, the Aqueduct took a sinuous route in order to bypass ridges lying in its path, although at two locations it was carved as a tunnel: a 400 meters long section under Bethlehem and a 370 meters section under Jabel Mukaber. At Rachel's Tomb the aqueduct split into two, a lower aqueduct running to the Temple Mount and an upper aqueduct leading to the pool near the Herodian Citadel. Until recently the upper aqueduct was thought to have been constructed 200 years after Herod's reign, the work of Legio X Fretensis which resided in Jerusalem. Recent studies, however, indicate that the Legion only renovated the aqueduct which had been partially destroyed.