Finish the Third Era with at least 2 Upgraded Great Projects
The most difficult thing about upgrading Great projects is the sheer unpredictability of the requirements that will appear. As such, here’s our recommendation: Concentrate your Biome. If you know that your ultimate attempt will take place on a forest then focus on developing the Forest Giant’s Fruit Aspect alongside the Swamp Giant’s Reaction Aspect for Iron.
Analysing what resources you’ll want to grow will help you work out which ambassadors need to go where, and concentrating on one biome (post ambassador farm) will help you use a researched stable of resources rather than scrabbling around trying to answer a variety of demands.
For us, it’s always the Forest. Orange Trees, Pear Trees, Blue Whales; Food is arguably the easiest resource to mass produce and this is normally the main resource when it comes to fulfilling forest Project requirements.