Touted as the ‘Sunken Garden’ (Çukurbostan) during Ottoman times, and currently known as the Karagümrük stadyumu (or Karagümrük stadium), there is an expansive area in modern-day Istanbul that has a bit of exalted history to it. How so? Well, as it turns out, the football stadium is actually an extant specimen that aptly demonstrates the advanced degree of Roman engineering ability. To that end, the site was a full-fledged Eastern Roman (Byzantine) built open-air cistern with impressive dimensions of 244 m (801 ft) length, 85 m (279 ft) width and 14 m (46 ft) depth!
Presently located within the walled district of Fatih, the humongous cistern design is estimated to be from the period when Emperor Theodosius II ruled, during the first-half of 5th century AD. Theodosius II is already known for the magnificent Theodosian Walls of Constantinople, and it was under his patronage that this huge undertaking was started by then-praefectus urbi of Constantinople, Aetius. In fact, most historians pinpoint the actual date of construction to be in the year 421 AD.
In terms of orientation, the Cistern of Aetius was designed in a parallel manner to the main thoroughfare of the super-city (also known as Mese), while it was supplied by water from the Valens Aqueduct, a gargantuan 971 m (3,200 ft) long Roman water-carrying system built in the late 4th century AD. As we mentioned before, the Cistern of Aetius itself was very large – so much so that it was used a reference point for recognizing other eminent buildings in the vicinity. To that end, the 290,360 cu m structure had a capacity of holding 66–79 million US gallons of water with parameter walls as thick as 5.20 m (17.1 ft).
Many experts believe that the Cistern of Aetius exhibits ‘opus listatum‘, an intricate Roman method of construction that entailed alternating layers of bricks and stones. As for the purpose of the herculean effort, there are hypotheses that relate to the cistern being used to supply water to the moats beyond the huge city walls. In any case, the reservoir went dry by at least early 16th century, as evidenced from the accounts of famous French topographer Pierre Gilles. And finally after almost 300 years, the engineering marvel was ‘practically’ transformed into a large sports ground (in 1928) by the newly established government of Republic of Turkey.