Cistern of Philoxenos

The Cistern of Philoxenos, known in Turkish as Binbirdirek — "a thousand and one columns" — is the second-largest surviving covered cistern of Byzantine Constantinople, surpassed only by the Basilica Cistern a few hundred metres away. Built likely in the 4th or 5th century to supply water to the imperial city, it takes its name from the senator Philoxenos, to whom a Byzantine source attributes its construction. Its most distinctive structural feature is a double-stacked column system — two tiers of columns placed one atop the other — a technique unique among the city's cisterns that allowed the builders to achieve greater ceiling height. Open today as a museum, the space offers visitors a cool, hushed atmosphere far removed from the bustle of the surrounding old city.