Turkish officials confirm discovery of extensive tunnel network beneath Hagia Sophia

Turkish Minister of Culture and Tourism, Mehmet Nuri Ersoy, has confirmed the existence of an extensive system of subterranean galleries, corridors, and tunnels beneath the historic Hagia Sophia. During a press conference in Kahramanmaras on September 17, 2026, the Minister noted that these underground structures span a total length of approximately 9 kilometers. Some sections of the network are currently inaccessible due to localized collapses.

Authorities are presently conducting intensive cleaning, restoration, and structural reinforcement operations to address issues such as humidity and debris. These measures are described as the most comprehensive intervention in the history of the Turkish Republic, aimed at preserving the 1,500-year-old monument for future generations. The Minister previously alluded to these tunnels in February 2026, dating certain sections to approximately 1,600 years ago.

While the primary goal remains the stabilization of the site, Minister Ersoy indicated that the government is evaluating the possibility of opening safe and secure parts of the underground network to the public once the restoration work is complete.