Kar-Charrat

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

Indigenous life
Much of the planet is dense rainforest. It rains near constantly and has an abundance of insects. When disturbed, freela birds make a shrieking noise that can be heard from far away. The least understood creatures are the native Kar-Charratans, an intelligent aqueous life-form whose failed attempts to communicate have, in part, led them to being called the "phantoms of Kar-Charrat". (BFA: The Genocide Machine)

Visitors to the planet
Few visited the planet because it is 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 had visited multiple times without being aware of the ziggurat. On the 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 of his success, a Dalek Destroyer entered geo-stationary 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)