A visit to the dam brings home the immense technological feat and allows you to gaze out over Lake Nasser, created by the blocking of the river, which is now over 500 km (310 miles) in length, spanning the border with Sudan.
The dam is the only place from which the entirety of Lake Nasser can be seen. 
mnli hypothesis: The dam is the only place from which the entirety of Lake Nasser can be seen.  premise: A visit to the dam brings home the immense technological feat and allows you to gaze out over Lake Nasser, created by the blocking of the river, which is now over 500 km (310 miles) in length, spanning the border with Sudan.