Engineers and archaeologists have successfully deployed a revolutionary 'Acoustic Holography' system to survey the Great Wall of Gorgan in northern Iran. This non-invasive technology uses sound waves to create high-resolution 3D maps of the interior of the wall's massive red-brick structure. The survey has revealed a series of previously unknown internal voids and specialized drainage chambers designed to prevent water pressure from collapsing the fortifications during seasonal floods.
This technological breakthrough provides critical data for the ongoing conservation of the 195-kilometer-long Sasanian-era defensive line. By identifying structural weaknesses without excavation, preservationists can now target specific areas for nanomaterial reinforcement. The success of the Gorgan project has sparked interest in applying acoustic holography to other large-scale ancient masonry structures, such as the Roman frontiers and the Great Wall of China.