Science-led restoration of Istanbul’s iconic Hagia Sophia advances on schedule

ISTANBUL

The large-scale, science-led restoration of Istanbul’s Hagia Sophia is progressing in full compliance with the planned schedule, successfully uncovering long-hidden underground tunnels and structural layers beneath the iconic monument, the culture minister has said.

“No intervention is undertaken without exhaustive scientific analysis and a commitment to meeting the rigorous requirements of modern conservation principles,” the Culture and Tourism Minister Mehmet Nuri Ersoy said on Feb. 27 regarding the work at Hagia Sophia and the nearby Blue Mosque.

According to Ersoy, teams conducted soil testing, load-bearing analysis, ground-penetrating radar scans and vibration measurements prior to installation and excavation works.

Only after receiving positive reports from scientific committees did the restoration move forward.

Inside the complex, particular attention has been given to protecting historic marble floors and interior spaces.

“We have implemented a multi-layer temporary flooring system to ensure both weight distribution and ground protection. Steel platform fabrications have also been completed, with elevator and staircase systems installed for access,” Ersoy said.

Work is currently continuing around the base and lower sections of the main dome, where structural reinforcement is underway.

One of the most closely watched aspects of the project involves Hagia Sophia’s underground tunnels and hypogeum — ancient subterranean burial structures that have long fueled public speculation.

Ersoy confirmed that extensive cleaning operations are being carried out in the western garden and northern facade areas by specialized teams.

Across seven tunnel routes, a total of 1,068 tons of soil has been excavated so far, allowing the tunnels to be fully cleared and documented, according to the minister.

“The goal of all these efforts is to reveal the monument’s historical layers, identify structural risks and secure this cultural heritage site in the safest possible way,” Ersoy said.