Roman Fort Segedunum (Milecastle 0)

In Wallsend, Tyne and Wear, England, the Roman Fort of Segedunum, also known as Milecastle 0, marks the eastern terminus of Hadrian's Wall.

The existence of Milecastle 0 as a distinct structure preceding the construction of Segedunum Fort is debated by historians, with no archaeological evidence found to date. It remains unclear whether the decision to build forts along the wall predated its extension to Wallsend, suggesting Milecastle 0 might never have been built. Little is known about its associated turrets, 0A and 0B.