Kar-Charrat

Kar-Charrat was a remote planet close to the edge of its galaxy and the location of the Library on Kar-Charrat.

Indigenous life
Much of the planet was dense rainforest. It rained almost constantly and had an abundance of insects. When disturbed, freela birds made a shrieking noise that could be heard far away. The least understood creatures were the native Kar-Charratans, an intelligent, aqueous life-form whose failed attempts to communicate led them to being called the "phantoms of Kar-Charrat". (BFA: The Genocide Machine)

Visitors to the planet
Few visited the planet because it was a twelve day flight from any major space lane. However, students did come from time to time to study the ziggurat and a few time sensitives were aware that the Library on Kar-Charrat didn't vanish centuries ago.

Time Lord technicians were present to install the defensive grid for the Library and the Doctor visited often, unaware of the ziggurat. On the Seventh Doctor's last trip before the Library was destroyed, he brought Ace with him.

Dalek invasion
After the Daleks became aware of the Library, they made a preliminary attack to test the defences. Through the use of time corridor technology, they set up a trap in Kar-Charrat's past to capture a time sensitive. Once Scout Seven reported to the Dalek Supreme on his success, a Dalek Destroyer entered geostationary orbit of the planet. With the help of the Kar-Charratans, the Daleks were defeated and the remaining Daleks left the planet, their mission unsuccessful. (BFA: The Genocide Machine)