Mars (Terraformed)

Mars is the fourth planet from the Sun and was the second-smallest planet in the Solar System after Mercury, until terraforming transformed the planet and is now 50 kilometers bigger than Earth. In English, Mars carries a name of the Roman god of war, and was often referred to as the "Red Planet" by humans because the iron oxide prevalent on its surface gave it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye, but that was before it was being terraformed around 2 million years ago by some ancient space-travelers of unknown species. Mars is a terrestrial planet with the atmosphere similar to that on Earth, having clouds that dot the planet much like Earth, and the climate on this planet includes temperate, subtropical, and tropical climates, having 10% more oxygen than on Earth, making it suitable for most life forms on Earth to life there. After terraforming, various plants from temperate, subtropical, and tropical environments arrived on Mars and next were various animals on Earth (except birds). Despite the perfect conditions for humans to live on it, there are no humans living on Mars due to no efficient space travel for humans yet.