When I visited the Pyramids, I first felt underwhelmed—they looked like mere piles of rocks. Coming from Sri Lanka, the ancient hemispherical stupas of my country seemed to be more complex structures (in an engineering sense).

...then I realized that when our stupas were built, the Pyramids were already ancient.

Something I find just as impressive is how far south ancient Egypt extended—not just to the border of contemporary Egypt ("Khemet"), but also to modern Sudan ("Wawat" and "Kush").

Given that this was 4000+ years ago, the logistical and administrative challenges of maintaining such a vast empire must have been incredibly challenging.