Kenaibrara was a large, floating artificial habitat, one of hundreds of biomes making up the Web of Worlds in the First Federation. It was located within the atmosphere of the class J gas giant Cherela.
History and specfics
Kenaibrara was a nature preserve. It was terraformed into a tropical rainforest with high humidity. Trees predominantly had violet and magenta-colored leaves.
In 2269, following the collapse of the Fiilestii module, Aluu Ne-Kewii invited Spock, Hikaru Sulu and David Bailey to meet with a dissident faction of the First Federation in Kenaibrara, which included Kasan Tor and Balok. With his interest in botany, Sulu was far more appreciative of the habitat than Spock, who found the humidity uncomfortable. Ne-Kewii agreed to smuggle parts to facilitate repairs to the USS Enterprise, which had been damaged during its attempt to rescue the doomed Fiilestii, and Balok offered Spock their scientific research proving that the Web of Worlds had become structurally unsafe. (TOS novel: The Face of the Unknown)