Starting roughly 23 million years ago in the oligocene the Great Rift Valley in east Africa and the Middle East begins a massive volcanic activity and the rift begins to spread quickly. 21 million years ago, the Red Sea begins to spread north and the Dead Sea becomes a northern extension. The Red Sea joins the Mediterranean Sea, the Sinai peninsula becomes an island. 18 million years ago, the horn of Africa begins to separate from the rest of the continent of Africa. The large rift lake begins to slowly empty northwards into the extending Red Sea.