Old Fort

The Old Fort was a massive Nordic fortress built along the southern border of Skyrim during the reign of the First Nordic Empire. The Old Fort is believed to have been built by some of the earliest Nordic settlers in Skyrim and is dated to be more than 3,000 years old (this is dated from 2E 864, so the Fort could be more than 4,000 years old). Despite its age, the Old Fort is considered one of the most impressive examples of Nordic architectural achievement. The Fort was known to have towering walls built out of enormous porphyry blocks fitted together without seam or mortar.Pocket Guide to the Empire, First Edition: Skyrim It was largely thought to be impregnable. 
==References==
es:Fuerte Viejo
Category:Lore: Skyrim Locations
Category:Lore: Forts