In the attached photo we can see a detail of the outer masonry of the Great Pyramid. The stone surface shows signs of water erosion damage. From this it can be deduced that the pyramid had to be under water for a long time, and moreover at a time when it was already missing the outer lining.

The questions are:

• When did the outer casing get damaged?
• When was the water level last so high that it could damage the masonry?

Water erosion detail