Vortis

Vortis is a planet in the Isop Galaxy, home to various native insectoid species, including the Menoptera, the Optera, the Zarbi and the Venom Grubs.

History
Originally a world of flower forests, the Doctor had visited there in his first incarnation. The native species of the world lived in harmony.

After the invasion of the Animus, the planet had changed into a world with a thin atmosphere, low oxygen, natural crag-like rock formations and pools of acid. With the destruction of the Animus, the Doctor hoped that Vortis could once more regain its verdant beauty. (DW: The Web Planet)

Many years later, Vortis drifted into the neighboring Rhumos system and became disputed territory for the Rhumons, who were in the midst of a civil war. The Animus, also, had not been completely destroyed, and a seed of it survived. With the destruction of this seed yet again with the help of the Doctor, Vortis eventually was left to regain its beauty and the Rhumons declared Vortis neutral territory and hoped the other Rhumons would learn of this, ending the war and bringing the Rhumos system to peace. (MA: Twilight of the Gods)