Theodosius Cistern

The Theodosius Cistern, also known as Şerefiye, lies beneath the streets of Sultanahmet in Istanbul. Built between 428 and 443 under Emperor Theodosius II, it supplied water to the Great Palace, baths and fountains of Constantinople. The rectangular underground reservoir measures 45 by 25 metres and is supported by 32 monolithic marble columns from Marmara Island joined with iron clamps. Today it operates as a museum with sound-and-light shows and preserves the spirit of Byzantine engineering.

The Theodosius Cistern is slightly curved to distribute water pressure evenly, while mysterious carved heads with bear-claw motifs appear in its upper sections, giving the structure a distinctive character and symbolism.