Kronos

Kronos, known and the Klingon language as Qu'Nos, is the home planet of the Klingons and technically a member planet of the Federation, by means of an alliance between the two civilisations.

Kronos is a planet mostly consisting of wasteland, and its only moon is in pieces, having been destroyed during one of the frequent Klingon Civil Wars.

The many cities on Kronos mostly consist of towering structures of radical design and composition, with some being made of materials that allow them to be built in ways that would be physically impossible for Earthern construction.

The space around Kronos is heavily guarded, and close proximity to an iron oxide nebula gives the planet a constant red sky. The Klingon warbirds that surround Kronos as specifically adapted to withstand the copious amounts of oxide in the surrounding space, but many other ships that enter Kronos space suffer serious mechanical faults, giving Kronos a natural defence.