Visitors to these sites had one particular religious ritual that may strike some as strange: they carved graffiti in important and sacred places.
In the shadow of the pyramids of Giza, lie the tombs of the courtiers and officials who built these vast structures.
Ancient quarry workers left messages carved on walls like a 4,500-year-old form of social media.
Cosmic particles called muons may revolutionise many areas of science.
The belief that ancient Egyptians needed help from supernatural beings to built the Giza pyramids relies, unavoidably, on racism and colonial attitudes.
Robots can explore where humans fear to tread.