1,500-year-old underground tunnel found in Istanbul

A secret underground passageway was uncovered during ongoing archaeological excavations in 1,500-year-old St. Polyeuktos Church in Istanbul’s Saraçhane Archaeological Park, a complex that dates back to before the construction of Hagia Sophia.

A previously unknown underground passage was found about 20 meters (65 feet) from the nearby Haşim Işçan Passage. The underground passage, which contains mosaics and stone inlays, has impressed researchers with its carved marble blocks and reliefs.