The largest country in the Arabian Peninsula is Saudi Arabia. It occupies a significant portion of the peninsula and is known for its vast deserts, including the Rub' al Khali or Empty Quarter, the largest contiguous sand desert in the world. Saudi Arabia is a key player in global oil production, possessing some of the largest reserves. The country is also culturally significant due to its historical ties to Islam, including the cities of Mecca and Medina.