Semna

Semna was a group of Egyptian fortresses at the southern end of the Second Cataract of the Nile in Nubia, in present-day Sudan. Senusret III of the Twelfth Dynasty fixed the frontier there in the 19th century BCE with boundary stelae forbidding Nubians to pass north except to trade. The forts and their temples were flooded by Lake Nasser after the building of the Aswan High Dam, though the temples were moved to Khartoum.