“Sunken Palace” is Istanbul’s largest underground cistern. It is the only one in the city that has been renovated and opened for public viewing. The cistern was constructed during the reign of Constantine I in the 4th century and was enlarged by Justinian I in the 6th century. For much of the Ottoman period it served as little more than a well and a fishing hole for the locals in what is now Sultanahmet.
In 1987 the cistern underwent massive restoration work, which included the removal of 50,000 tons of mud and water. Today Yerebatan Sarayi is a major tourist attraction and offers cool respite from Istanbul’s searing summer heat. Pulsing lights, water dripping from the ceiling and eerie music played over strategically placed speakers add an air of mystery to the place
The cistern is 140 by 70 meters (459 by 230 feet) and holds 80,000 cubic meters of water. Supporting the ceiling of small domes are 336 columns, many of which are mismatched and appear to have been pilfered from elsewhere. The purpose of the two large Medusa heads supporting a pair of columns on the north side of the cistern is unknown, since they were not discovered until the cistern was drained..
The hippodrome was an immense construction 480 meters length and 117.5 meters wide; it could seat, according to estimations one hundred thousand spectators. It was build in 203 by the Emperor Septimus Severus and later on Constantine the Great extended and remodeled it.
As Haghia Sophia was the center of religious life, the hippodrome was the center of the civil activities. The interests and passions of the population was divided between theological controversy and chariots races on the hippodrome.
Today you can only see some monuments where the hippodrome was. If you are curios and want to see how was the old Constantinople city center click here ! The central line, or spina of the hippodrome was marked by obelisks and columns, three of which are still outstanding monuments at Sultan Ahmet square (see picture bellow: the red line is where the hippodrome was located, behind it you can see the Blue Mosque and Saint Sophia).