Early settlers arrived in Egypt around 3100 BC, settling in desert areas. The first stone pyramids were built around 2700 BC, including the large pyramids at Giza used to hold pharaohs. Hieroglyphics developed as a early writing system, helping Egyptians communicate. By 1200 BC, iron began replacing bronze which strengthened technology and infrastructure. Egypt experienced many foreign rulers and periods of unity and division over thousands of years of history and development.