Chogoris
Chogoris (also known as Mundus Planus) is a feral world, homeworld of the Primarch Jaghatai Khan and current homeworld of the White Scars chapter. It's a pretty decent place to look at. Quite a few mountains and fertile land. Though its society is filled with warring tribes who the White Scars look at the strongest kids and pilfers them for recruits.
History
Remember what I said about warring tribes? Still like that. There was this guy called Palatine who had the largest empire and well-trained and disciplined soldiers. The Khan landed somewhere else and then made an empire of his own. He then killed the son of Palatine after he and some other blokes tried to capture the Khan after he got caught in an avalanche. Then Palatine sent an army but got smacked the fuck down and fell back to the capital whilst his army was utterly destroyed. Then after literally every other place on the planet was captured or looted, the people revolted and gave Jaghatai Pala's head when the Khan knocked on the capital's door. Peace came to the planet and everyone was finally unified. Then the Emperor arrived and Khan got the chance to get tonnes of super soldiers and purge the xenos, the mutant and the heretic. Also got a cool bike.
After Khan left, the planet devolved back into warring tribes again. Though the White Scars believe he let that happen on purpose so there'd always be a supply of strong recruits for the legion (and later on, chapter).
Post-Heresy
Not much, the place is a popular pillaging stop for Red Corsairs and the Dark Eldar. The knife-eared bastards started looting everything not nailed to the floor (nails and floors being a luxury for most of the populace), and the Khan had to get back home to set things straight. The Necrons attacked and got destroyed. Though in the third war for Armageddon Huron Blackheart started looting Chogoris, so the White Scars had to leave Armageddon and purge the heretic. During the Damocles Crusade, the White Scars had to rev up the whole thing to rush back home to scare the Red Corsairs off their trophy collection stock once again. Lucky bitch!
May or may not be a Tomb World, considering a Necron Tomb ship randomly stopped by once to bombard a seemingly random and unpopulated area of the planet before getting blasted by the planet's defenses.
Following the opening of the Great Rift, the world has come under frequent siege by the forces of Chaos, and the Stormseers fear that the world may be in danger of corruption. the Red Cosairs had managed to invade the planet and is currently entrenched in the system.