During the reign of Emperor Hadrian, the significant structure built was Hadrian's Wall. Constructed around AD 122, this fortification extended across the northern part of England and was designed to protect Roman Britain from invasions by tribes from what is now Scotland. Hadrian's Wall represented the northern limit of the Roman Empire and was a remarkable engineering feat, featuring a series of forts and watch towers. The wall symbolized Rome's power and military strategy, while also facilitating trade and communication along the frontier. Its remains are now a UNESCO World Heritage Site and a prominent symbol of Roman history.