Too often, Egyptian itineraries give Cairo short shrift. Admittedly, this vast metropolitan area of some 21 million people has problems with air pollution, chaotic traffic and shoddy and illegal construction. But Cairo is an utterly fascinating place to visit; its complex history, like Jerusalem’s, is layered with the imprints of Jews, Christians and Muslims. On this recent visit, we spent a total of five nights there, but even so, we had to skip a number of major attractions entirely. When the much-delayed Grand Egyptian Museum finally opens in Giza, theoretically in November, Cairo will merit yet more time.