The Tessegri module 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.
It was a domed metropolis approximately 1,000 km wide. At a glance the biome resembled New York City with a larger Central Park, except that each building was an arcology shaped like a ziggurat and was surrounded by huge parkland, which was amenable to the Tessegri, who loved to walk, jog or run everywhere. Despite their massive size, interiors were well lit and ample light was reflected outside to the ground. The roof of the largest arcology, kilometers high, provided a stunning view of the biome.
A fine vegetarian restaurant overlooked the interior of one of the arcologies. A control center managed the artificial gravity system which kept the module afloat in the atmosphere, powered by the planet's massive electromagnetic field.
In 2269 James T. Kirk and Nyota Uhura toured the Tessegri module. Later, after the collapse of the Fiilestii module prompted the arrest of Kirk as a scapegoat, Spock meet with Chief Protector Nisu Miratuli of the First Federation at the vegetarian restaurant. Spock presented her with dissenters' research findings concerning the instability of the Web of Worlds. Nisu offered him a home instead, and insinuated that the research was meant only to prove Kirk's innocence.
When remote devices were being installed in control centers throughout the Web of Worlds to attempt to stabilize all the modules, Kirk took a team to install one device at the Tessegri module. (TOS novel: The Face of the Unknown)