Perūn

Perūn is the fourth planet from the Sun (not our Sun) and the only other planet besides Terra to support life. The vast majority of the surface of Perūn is land consisting of mountains, a large canyon system spanning the equator, and desert plains. Small oases and ice lakes under the ground make up all of the water found on the planet.

Perūn's atmosphere consists mostly nitrogen and oxygen. The gravity on the surface is equivalent to about 1.20 G. The surface is generally very cold to warm, but can get extremely hot during sandstorms. The composition of the planet includes an abundance of cobalt, iron, magnesium and nickel making the mining sector of the planet a particularly fruitful business.

Perūn is theorized to have formed about 4 billion years ago. The only life besides homo-sapiens that exists on the planet are some small plants and an abunance of fungi, including forms of mycelium.

Human Colonization
Perūn was overlooked for a long time due to it's smaller stature and more hostile weather patterns that made the planet difficult to learn about. Mars was colonized before Perūn and declared independence from the U.N. almost immediately after becoming self-sufficient, making it the more hotly contested planet and eventually even suffering from a civil war.