Why don't we create a giant New York-esque city that we create collaboratively? It can have skyscrapers that we can add floors to similarly to how streets are created!
Yeah! I like the idea that we start to delve into a more urban landscape as we progress eastwards/westwards through Groddle (like the PS3 game, Flower... watch just a snippet from each level, one to six and you'll see what I mean: www.youtube.com/user/Astute... )