Sigma Iotia II
From Star Trek : Freedom's Wiki
Sigma Iotia II is the second planet in the Sigma Iotia system, homeworld of the Iotians.
The Earth vessel Horizon visited the planet and left behind a book called Chicago Mobs of the Twenties in 2168. This book became so influential among the population that they completely mimicked the criminal underworld society of Prohibition-era Chicago on Earth.
USS Enterprise came to visit Sigma Iotia II in 2268 in an effort to investigate the missing Horizon and undo the cultural contamination caused by its visit. (TOS: "A Piece of the Action")
