Traveling along the Nile takes you through both space and time. Ancient Egyptian civilization as we know it came alive around 3100 [bc], when Narmer united Lower and Upper Egypt, and breathed its last breath in the 4th century [ad] during the simultaneous rise of Christianity and collapse of both paganism and the Roman empire. The monuments you see are the accretions of centuries of dynastic power, ritual practice, artistic expression, and foreign interference that continually adapted and renewed an inspiring system of beliefs.
You don't need to know any of this to appreciate the beauty and refinement of the paintings in Seti I's temple at Abydos or the majesty of the temples at Karnak. Just consider the high level of societal organization that it took to conceive and create what the ancient Egyptians left behind. Looking back at their civilization from the third millennium of the Christian era, we are gazing eye to eye with our equals in ambition, achievement, and, in many ways, technology.