Early Egypt was located along the fertile Nile River valley. The deserts and predictable Nile floods allowed Egyptian civilization to develop in relative isolation. Major periods included the Old Kingdom, Middle Kingdom, and New Kingdom. Egyptians made advances in math, astronomy, medicine, and built the iconic pyramids and mummies as part of their religion which emphasized an afterlife. The Rosetta Stone, discovered in 1799, was instrumental in deciphering hieroglyphs and providing insight into Egyptian history and culture.