The pyramids were under construction during the period 2500 BC to 2100 BC, which makes one wonder why the Egyptians didn't notice they were under water a full year. Oh well.
Perhaps the Egyptians weren't under water.
Not only does it explain the carving out of the Grand Canyon, but also reveals how the Egyptians built the pyramids.
Being expert boat builder, the Egyptians were sub-contracted by Noah to build the Ark, and in so doing gave Noah the time for his administrative duties (passenger gathering and ticketing)
Meanwhile, understanding about water, the Egyptians built a couple of spare Arks of their own plus large barges on which to put the pyramid stones
So, as the flood waters rose, the Egyptians were able to build the pyramids higher and higher -- which took a mere forty days and forty nights (lots of overtime pay there) -- by floating the stones into place with ease and accuracy.
Where's that Pianistimo lady?
I'm sure she'd agree with this idea and put her own unique spin on it.