The original City of David was not built where today's Old City stands but on a ridge, outside the present Old City walls. Excavations in and around the City of David uncovered several ancient water systems that brought water from the Gihon Spring in Kidron Valley to pools inside the city, including the Pool of Siloam. For Christians, the Pool of Siloam is where Jesus restored a blind man's sight and for Jews, it is significant as the water source for ritual purification in the Temple. Today the Pool of Siloam is outside the walls of the Old City of Jerusalem on the slopes of the City of David, the original site of the City of Jerusalem.
By the 17th century BC, the Canaanites (Jebusites) had built a tower protecting Gihon Spring, connected to the city walls by fortifications and a tower protecting the pool. Excess water was released into the Kidron to irrigate farmland but this gave attacking troops access to freshwater. The large pool or basin was referred to as the Upper Pool. King Hezekiah(715BC-c.687BC) cut off access to the Gihon Spring and Upper Pool and built a new underground tunnel to protect Jerusalem's water source (2 Chronicles 32:2-4).
In 2 Kings 20:20, we read how King Hezekiah built a pool and conduit to bring water into the city. This c.8th century BC underground channel is known as Hezekiah's Tunnel. The tunnel is 533m long, an average of 60cm wide, and 2 meters high. Hezekiah's Tunnel brought water from the spring to the Pool of Siloam, also known as the Second Temple Pool and the Lower Pool.
The Pool of Siloam was still in use during Jesus' lifetime. In John 9:7 we read how Jesus rubbed mud on the eyes of a blind man and told him to wash his eyes with the waters of the Pool of Siloam. The blind man's sight was miraculously restored. At the time, the Pool of Siloam would have been a gathering place where people came to get fresh water and where pilgrims stopped for water on route to the Temple. The pool may have been used as a Jewish ritual bath (mikvah) or Roman-style baths for swimming. Following the First Jewish-Roman War in 70AD the pool was destroyed and over the years, rain-washed soil down from the surrounding hills until the pool was covered completely and forgotten.
In the 5th century AD, the Byzantine Empress Eudocia built the Our Savior the Illuminator Church and a pool at the end of Hezekiah's Tunnel to commemorate the site of Christ's miracle. For years this was the traditional site of Christ's miracle. This narrow rectangular pool has survived and today is surrounded by high stone walls. This is where walkers exit Hezekiah's Tunnel. The ruins of the Byzantine church can be seen nearby.
During the excavation of the City of David in 2004, the real biblical Lower Pool where Jesus cured a blind man was uncovered just 50 meters from the Byzantine pool. Excavation revealed five steps on three sides of a 60mX50m trapezoid-shaped pool dating to the 1st century AD. It was only possible to excavate a section of the pool which lies partially under a beautiful garden owned by the Greek Orthodox Church. Today access to Hezekiah's Tunnel is through the excavated City of David. Visitors go down Warren's Shaft (an ancient Canaanite water shaft) to reach the tunnel. They can then walk along the tunnel to the Pool of Siloam. You need to use a flashlight and come prepared to walk through the water. Alternatively, the dry Canaanite tunnel starts at the same place and brings you to the Pool of Siloam.