Simplify the following text for a Grade 11 native English-speaking person.
Original: Once thriving with the Nile that flowed right into the Giza Plateau , the pyramids of Giza were built overlooking the ancient Egyptian capital city of Memphis , which was near modern day Cairo .
Simplified: Once thriving with the Nile that flowed right into the Giza Plateau , the Pyramids of Giza were built overlooking the ancient Egyptian capital of Memphis , which was near modern day Cairo .