Egypt is one of the worlds oldest civilizations. Cairo is Egypt's ancient capital and is the largest city in Africa and a tourist centre. Egypt depends on the River Nile for much of its water, transportation, and food. The sea yields sponges and pearls besides a variety of fishes. The chief agricultural products are wheat, barley, onions, cotton, and rice. Every year, millions of people flock to Egypt to see Pyramids, Sphinx, and other remains of the country's ancient past; such as the tombs of Kings and queens and the temples at Karnak and Luxor. The oldest pyramid is the step pyramid at Saqqara. The tourist trades provide growing number of jobs.