Hagia Sophia's seismic retrofitting and preservation efforts

Hagia Sophia in Istanbul, a former cathedral-turned-mosque-turned-museum-turned-mosque-again, is undergoing seismic retrofitting to protect it from earthquakes. The structure has collapsed multiple times since the 4th century, including its dome in 558 and partial collapses in the 10th and 14th centuries. The B1M video explains the engineering behind its central dome and sub-domes. Eight green marble columns from the Temple of Artemis support the upper floors, and a red stone from Egypt marks where emperors were crowned. Current restoration focuses on the dome, floors, columns, and mosaics. The project aims to ensure the building stands for another 1,500 years.