So I saw the Tropical Skyrim mod and I love how it give skyrim a whole new feel. I would love some more extreme variations of the game. One of my suggestions would be Gallifrey from doctor who. With some retextures: orange sky, red grass, and silver leaves you would have Gallifrey. I will say there are a lot of grass mods that would need to be converted to red but I think the game would be great. http://th04.deviantart.net/fs71/PRE/i/2013/068/0/f/gallifrey_from_mount_perdition_by_lupus_deus_est-d3epdag.jpg From the planet's surface, it boasted an orange sky, snow-capped mountains, fields of red grass, and trees with silver leaves. These reflected the morning sunlight, making it look like the forests were on fire. There were also green forests, golden fields and red deserts. But overall it seems to have been a much drier world than Earth. The Sixth Doctor once declared the climate to be "like the Serengeti all year round". There was also a river called Lethe. Gallifrey had at least two large moons and a ring system, similar to Saturn in Earth's solar system. One of the moons was the copper-coloured Pazithi Gallifreya, which shone so brightly it could be seen during the day.
