From Archeologists Discover Segment of Jerusalem Storm Drain from Second Temple Period:
A 70-meter-long segment of Jerusalem’s central drain dating from the Second Temple period was discovered Sunday by the Israel Antiquities Authority. The segment is located between the Temple Mount and the Pool of Siloam. It stretched underneath the Old City’s main street and cleared rainwater from the areas it served. It is made of massive slabs of stone, and is about three meters high and one meter wide.