This film is often regarded as the best surrealistic film of all time. Like in his previous film "un chien andalou", Bunuel introduces us a film with a cock-and-bull screenplay. In this movie, he's using the power of his imagination and this is one of the surrealism's goals. The movie starts with a documentary on the scorpions, then some thieves are discovering four archbishops on the rocks, next, come the founders of Rome. Later, in Rome, a young woman is finding a cow on her bed; during a reception, in a beautiful castle, a tipcart full of workers is crossing the living-room and other weird events like these ones happen later..... It's easy to find out why this movie was forbidden for a long time in France (it was finally re-released in 1981). If you think that some elements of the story (if there is one!) like the four archbishops or the tipcart are funny, well they aren't. It's only his second film and Bunuel's showing us his obsessions: he's laughing at religion and upper middle class by ridiculing them and he is against the conformity. That's why his movie's got nonsense and even the title: why the Golden Age? However, behind all this nonsense, there is a love story between Gaston Modot and Lya Lys which is more sketched out than told.
Moreover, the film also created a huge scandal due to the last sequence. It was inspired by the most horrible French novel: "les 120 journées de Sodome" by the Marquis de Sade (Bunuel used to admire him). This French writer's novels were forbidden for a long time due to their violence and their philosophy. In the movie, the scene created a double scandal because the count of Blangis's got the Christ' head! This film is incredible and fascinating due to the screenplay and its unexpected events. If you want to discover Bunuel's films, this one is a good start