Finish an Era with at least 6 Villages that have 150 Village Prosperity
This development is really no where near as hard as it might sound at first. All you need to do is create a forest and swamp, encourage a project from these two villages (and grab the ambassadors with the appropriate Giants), and then place two more oceans followed by another forest and another swamp. Continue this process until the world is covered, moving from one village to the next.
With the world covered in developed minor villages you should return to the beginning and start replacing resources with those of a superior variety, or adding powerful aspects to them to encourage easy extra resources.
Remember to fill the Oceans with fish and this challenge should come easily.