The most interesting thing about Cairo, not including its pyramids, is something you'll find in a place called "Old Cairo." There is where the real essence of the city is. To pass through its streets, losing yourself among the markets and even learning to haggle, is one of the experiences that's not to be missed. It's also interesting to be able to go in a mosque, even though, of course, women have to be covered. Normally they don't let tourists in, but there are some the are ready for foreigners that they can go in if it's not during prayer hour.