Ancient Egypt was located in the fertile Nile River valley. The predictable flooding of the Nile allowed for reliable agriculture and helped the civilization thrive. Ancient Egypt was divided into three kingdoms that later unified under a single ruler known as the Pharaoh. Egyptians followed a polytheistic religion and had an advanced culture with accomplishments in architecture, mathematics, medicine and more. Significant figures included Queen Hatshepsut, the first female pharaoh, and King Tut who restored Egyptian religion after Akhenaten's attempt at monotheism. The Egyptian empire declined after 1000 BCE due to ineffective leadership and foreign invaders like the Assyrians and Persians.