I have a small bunch of slides that I am guestimating (for a variety of reasons) as being from around 1958. However, the two you'll see today must be from a few years earlier. Sometimes it can be hard to tell, but in each of these you can see the short-lived signs that showed guests the layout of the "land" they were about to enter.
I would be unable to resist this entrance! I have a friend who told me that he never went into Tomorrowland in the 50's because there was practically nothing to do. ZOIKS! I can think of at least a dozen things I would want to do!!