I watched this movie as a kid, and didn't like it. Story seemed too dark and meaningless to me at the time. Watched it recently after watching a youtube that explained its symbolism, and I was blown away. Youssef Chahine (and Salah Jahine in turn) turned out to be a true genius, not an idiot as I always assumed!
Every character in this movie represents part of the Egyptian (and generic Arabic) society across three generations. From the pre-1952 naivity, to the pre-1967 deceived (writers of this movie and their generation), to the post-war generation seeking to break away with both Nasserism, as well as colonialism that preceded it, to forge hope that can survive the modern world. The movie gives Nasserism and totalitarian Socialism their day in court, and accuses those who believed in them of being a waste of potential.
The cast is second to none. The songs are still popular to this day. Every sentence in the dialogue was intentionaly, and symbolizes something.
To understand the movie, you need a good grasp of the history and politics of Egypt/Middle East in the 20th century.
Oh, how have I grown up!