Great Northern Wall
From Guild Wars Wiki
Two Ascalonian soldiers standing before the massive Great Northern Wall (click to enlarge)
The Great Northern Wall began construction in 898 AE. At this time, before the start of the Guild Wars, the Charr threat was beginning to look more imminent. The wall was erected to protect the large bulk of the Ascalon empire, though many prominent cities still resided north of it - some examples being Surmia, Piken Square, and the Nolani Academy, which housed many scholars and was even where Ascalon's royal bloodline was educated.

