History of Saudi Arabia covers thousands of years with lots of people from different cultures living there. There was a culture called the Dilmun culture among them, which was very old and existed along the Persian Gulf. It was as old as the ancient civilizations of Sumerians and the Egyptians. Saudi Arabia had trading relations with many parts of the ancient world, but the hot and harsh climate had made large settlements difficult. Some settlements had always existed around oases; these are places in the deserts where growth and water are available. 