Two floating biodomes with a bridge connecting them. Biodome 1 is completely finished. It has terrain, a river, a lake, a mountain with a waterfall, trees, and a secret hideout. Biodome 2 only has trees; it's up to you to customize it better than mine. Biodome 1 has a river flowing through it that starts at a waterfall and flows out the side.

Spoiler Alert:

The hideout is inside the mountain. You have to float up the water fall and sort of jump to the right and their will be a trapdoor that leads into it.