Guests at DISNEYLAND today know that they can get to New Orleans Square and the Frontierland waterfront by walking through Adventureland. In fact, guests can pretty much roam around the entire west side of the park without having to re-enter the park's Central Plaza. This wasn't always the case, however.
In the 1950's and early 1960's, guests encountered a wall at the end of Adventureland. If they wanted to get to Frontierland, they had to walk back out to Central Plaza, make a left, then enter Frontierland through the main stockade. This caused numerous traffic problems and was rectified once New Orleans Square was built. The wall came down and traffic flowed freely out into the wild frontier.