Alexander the Great conquers Egypy and founds Alexandria in 332 B.C., A Macedonian dynasty rules until 31 BC.
The significance of this event is that a Macedonian dynasty rules for such a long period of time.
Egypt comes under Roman rule in 31 B.C., Queen Cleopatra commits suicide after Octavian's army defeats her forces.
The significance of this event is that Egypt is now being ruled by Rome.
Construction of the pyramids began around 2,500 BC this is a engineering achievement because at that time, and even today there is no buildings of comparison.
In 7000 B.C. people started to settle around the Nile River. This is significant because this is how Egypt began.