Vantex II
A city on Ventax II during the riots of 2367
Ventax II is the homeworld of the Ventaxians, a peaceful, agrarian society.
Over 1,000 years ago, the planet was divided in numerous highly-industrialized city-states who constantly warred with each other and destroyed great parts of the planetary ecology. Then, the planet's leaders came to reason and began pacifying the planet and cleaning the environment, using the newly-created story of Ardra to justify themselves to their people. The planet isolated itself from the rest of the galaxy, until it was again confronted with the outworld through a Klingon expedition in 2297. Sometime after this, a Federation science station was established on the planet.
In 2367, the planet fell into chaos when, according to the Ardra-story, a fabulous 1,000-year period of peace and wealth would come to an end and the planet would be turned over to Ardra. A con artist used this myth and modern technology to present herself as Ardra and to bring the planet under control, but her true identity was successfully revealed by the crew of the USS Enterprise-D.
The central government building of Ventax II is called the "Atheneum". (TNG: "Devil's Due")