Set on the Nile River, Cairo is a mega-city of of more than 20 million people, making it the most populous city in the Middle East and the second most populous in Africa — and it feels like it. The capital of Egypt is not an easy city, as it is loud, clogged and frenetic – and it might take a while to get used to the cacophony. But it is a small price to pay to experience the energy of the Mother of the World.