Some initial ideas:
- How Penicillin Changed the World
- How Deforestation Changed the World
- How Gaming Changed the World
- How The Telephone Changed the World
- How Social Networking Changed the World
With the idea of 'world' being affected I like the idea of several small floating worlds which you could walk around quite quickly such as in Super Mario Galaxy.
If the deforestation idea is chosen I'd quite like to look at paper craft like origami or very simple geometric shapes, such as http://zimandzou.fr/
For the more technological based ideas such as gaming or the telephone I'd quite like to look at pixelated and/or very simple low-poly models similar to the geometric paper crafted shapes.
For the Social Networking idea I'd quite like to look at perhaps the 'can and string' idea for communicating or paper aeroplanes flying across the small world.