An unprecedented retreat of the Alam-Kuh glacier in Iran’s Alborz Mountains has exposed the remains of a previously unknown 8th-century Sasanian-era fortress. The site, located at an altitude of over 3,500 meters, includes well-preserved stone barracks, a central watchtower, and a cache of iron arrowheads and leather armor that had been frozen for over 1,200 years.
Archaeologists believe the fortress served as a strategic high-altitude military post to monitor mountain passes during the transition between the Sasanian and Islamic periods. The discovery is providing critical data on how ancient empires maintained control over rugged borderlands and how they adapted their defensive architecture to extreme alpine environments.