Beta III
Beta III is an Class M planet in the C-111 system that is home to a species externally indistinguishable from Humans.
About 6,000 years ago, a leader and philosopher named Landru became deeply concerned that the wars raging on Beta III would destroy all life there. To solve the problem, he built an extremely sophisticated computer, also called Landru. Landru absorbed the members of Betan society, eventually exerting absolute control over the thoughts and feelings of the entire planetary population. Landru eliminated hate, fear, and conflict, put an end to war, disease, and crime. But Landru also eliminated the soul of the civilization. The people moved through their lives in a blissful daze – and nothing changed for almost 6,000 years.
In 2167, the Archon visited Beta III, and her crew encountered Landru. Many were absorbed into Betan society; many more were killed, and the ship itself was destroyed.
A hundred years later, the USS Enterprise visited in search of clues to the Archon's disappearance. She, too, was threatened by Landru. Captain James T. Kirk confronted Landru, and convinced it that it was harming the very society it was programmed to protect. Unable to resolve this paradox, Landru destroyed itself, leaving the citizens of Beta III free to govern their own affairs. The Enterprise left a team of sociologists and other experts behind to help them return their society "to a more Human form." (TOS: "The Return of the Archons")