The watchful eyes of a stone Medusa head staring as visitors pass by at the Basilica Cistern in Istanbul, Turkey, on Sunday.
The site, which was closed for renovation in 2020 due to the risk of collapse, has been restored by the Istanbul Metropolitan Municipality and is open to visitors again.
It is located in the district of Sultanahmet, within walking distance of other Byzantine and Ottoman-era landmarks such as the Hagia Sophia Grand Mosque and the Blue Mosque.
The Byzantine structure, which rests on 336 columns, was commissioned by Emperor Justinian and built in 532.
Also called the Underground Cistern, it is Istanbul's largest and most well-preserved cistern.
According to historical texts, more than 7,000 slaves were involved in its construction.
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