Pretty much everyone the world over, whether they are cycling fans or not, knows what the Tour de France is. But there are other Grand Tours with 21 stages, 20+ teams of 9 riders each and all that stuff. And the TdF isn't even anything like the "last of the season" like a championship match like the World Series of baseball, Super Bowl or NBA Finals. There is still the Vuelta de Espania still to come next month.
So why is the Tour de France so famous, and so well known? Is it just because it has the longest history as compared to other UCI Grand Tours?