This is an extensive explanation of the Tour De France. It discusses the history, the format and basic team strategy. Unless you are a real expert, there likely is much here that will be new to you.
For example, do you know what "cracking" is? Do you know all of the different types of jerseys that are assigned to riders. How about why the leader's jersey is yellow and not some other color? The video even gets into the medical aspects of the race upon individual riders.
The Tour De France originated in 1903, when a cycling journalist suggested a race to his editor, Henri Desgrange. Desgrange went on to create and oversee the race, which has changed a great deal over the years. At first, anyone at all could complete, but later the race was restricted to professionals.
The race has been held annually except for during the two World Wars. The teams are all pro teams except for amateur teams specially invited. There are time trials, flat stages, and mountain stages. Each Tour covers some 3000 km in 23 days (21 stages, two rest days), and there are 21 teams of 9 riders each. Each stage lasts 4-6 hours.
There is a lot of fascinating information here, pretty much any bicycling fan can pick something up from this. Even if you know it all, it is a good review. And it is all presented in a realistic fashion provides real-world observations along with formal rules.
Everyone who is going to watch the Tour De France on tv should watch this video at least one.