Early human settlements arose along the Nile River around 8000 BC due to its fertile soil and reliable flooding. Around 3000 BC, Egypt was unified under the first dynasty founded by King Menes. Egyptian civilization flourished for over 2000 years due to the Nile's predictable flooding and the geography which protected Egypt. Society was divided into classes like rulers, priests, merchants, and slaves. Egyptian culture made advances in areas like math, engineering, and medicine.