Workers constructing a sewer line in East Jerusalem last month discovered a 2,000-year-old water-supply system that—think about this—worked fairly well until the last century, LiveScience reports. The 13-mile long Lower Aqueduct, which was fed by a spring south of Bethlehem and runs through four modern-day Jerusalem neighborhoods, was built by kings governing Judea and environs from roughly 140 BC to 37 BC. City rulers kept it up over the years, covering the open channel with terra cotta pipe about 500 years ago. It remained a major water-supply source until an electrical water distribution system replaced it roughly 100 years ago, according to the Israel Antiquities Authority.
The IAA says it will cover part of the aqueduct "for the sake of future generations" and expose parts for access by the general public, Discovery reports. Meanwhile, archaeologists are marveling: "The aqueduct begins at the ‘En ‘Eitam spring, near Solomon’s Pools south of Bethlehem," says IAA Director Ya'akov Billig. "Despite its length, it flows along a very gentle downward slope whereby the water level falls just one meter per kilometer of distance." The original designers look pretty smart, too, having built the aqueduct in uninhabited areas where Jerusalem neighborhoods now exist, the Times of Israel notes. Other parts of the aqueduct system have been found before, including tunnels in the City of David and ones near the Sultan's Pool beside Mount Zion in Jerusalem. (Read more water supply stories.)