It wasn't too long before the Jupiter cloud city planners started building with algae. In the nutrient-rich environment, algae held together better than anything else, and with a little genetic tweaking it was as strong as steel.
This is a detail from an image by Eddie Del Rio, an illustrator and designer in Northern California. He has worked with Lucas Arts, Lucasfilm, Disney, THQ, Activision, and 2k. You can see more of his incredible work on his website.