About ten years ago I ran into a comment posted on some site that said something like, "If you want to see what really can be done, search YouTube for 'Greening the Desert by Geoff Lawton'."
On a whim, I did. That search changed my life. I found a video describing the transformation of a chunk of the worst desert in the world into a tropical oasis with almost no water. The guy (Geoff Lawton) who narrates the video didn't even want to film it, but was talked into sharing just one of his projects by a film-maker friend of his.
After some research I tracked down Geoff Lawton and joined one of his Permaculture Design Certificate courses. Now I have my PDC, and my daughter is about to receive hers from him, also.
Not sure where the original "Greening the Desert" video is, but here's one of the original postings of it.