What is the movie "Citizen Kane" about?

Citizen Kane is considered (at least by AFI and many film teachers, critics, etc.) to be the greatest movie ever made. It was directed by/starred Orson Welles as Charles Foster Kane, a newspaper tycoon that represented (in a very bad light) William Randolph Hearst, a powerful man at the time that happened to be a media titan, which made the movie kind of infamous. Basically it starts off with Kane dying and the last word he says before his death: “rosebud.” The whole movie is a history of his life and trying to find out what “rosebud” is, which you find out in the very last scene of the movie (I won’t tell you what it is unless you want to know). The mystery of “rosebud” is sometimes considered the greatest secret in the history of cinema-and it was also the pet name Hearst had for one of his mistresses. The movie starts from when he was a little boy in poverty to a young man trying to start his own newspaper with his best friend to finally becoming a powerful, corrupt and lonely man. He goes from the underdog to the hero to the villian to dead throughout the course of the movie. The reason a lot of film buffs find it so great is because it has a great storyline but also used a lot of techniques that had never been seen before, especially with camera shots. Then there’s some people who don’t like it because it is simply a movie that is 70 years old and in black-and-white.