The "fertile crescent" refers to an ancient area of fertile soil and important rivers stretching in an arc from the Nile to the Tigris and Euphrates. It covers Israel, Lebanon, Jordan, Syria, and Iraq. The Mediterranean lies on the outside edge of the arc. To the south of the arc is the Arabian Desert. On the east, the fertile crescent extends to the Persian Gulf. Geologically, this corresponds with where Iranian, African, and Arabian tectonic plates meet.