Persian Gulf flooding of the basin started 15,000 years ago due to rising sea levels of the Holocene glacial retreat. This inland sea of some is connected to the Gulf of Oman in the east by the Strait of Hormuz; and its western end is marked by the major river delta of the Shatt al-Arab, which carries the waters of the Euphrates and the Tigris. In Iran this is called "Arvand Rood", where "Rood" means "river". Its length is , with Iran covering most of the northern coast and Saudi Arabia most of the southern coast. The Persian Gulf is about wide
Persian Gulf gulf, historically and internationally known as the Persian Gulf after the land of Persia (Iran), has been disputed by some Arab countries since the 1960s. Rivalry between Iran and some Arab states, along with the emergence of pan-Arabism and Arab nationalism, has seen the name "Arabian Gulf" become predominant in most Arab countries. Names beyond these two have also been applied to or proposed for this body of water. Earliest evidence of human presence on Persian Gulf islands dates back to Middle Paleolithic and consist of stone tools discovered at Qeshm Island.The world's oldest known civilization (Sumer) developed along the