The first thing you need to know is how to get from the airport to your hotel. The best option is to arrange a pick up service with your hotel. If you have not booked a hotel room, you can try to take a taxi to the city center, but you have to know this is the worst way to start your travel in Egypt. Taxi drivers will try to charge you as much as they can, and will try to take you to one of their "recommended" hotels. If you need to negotiate with a taxi driver at the airport make clear you are talking about Egyptian pounds, because most of the times when you try to pay them, they will say they were talking about US dollars (that's 3 times the price in Egyptian pounds!). Fortunately taxi divers in the city of Cairo are much more friendlier.
The second thing you need to know is how to move around Cairo. Traffic is so chaotic in this city, that renting a car is an option I cannot recommend. You better use public transports. I knew buses were not recommended either, but I wanted to experience a bus ride. Now I am sure: you shouldn't take local buses. They are dirty and it is almost impossible to know where they are going. If you don't want to waste your time, don't take a bus.
I can only recommend taxis and the underground. Underground is usually overcrowded, but it is easy to use and cheap. The name of the stations is written in English. The only inconveniences are the heat and the crowds.
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