From: Star Trek: The Next Generation
Planet: Ventax II. Once-technological humanoid culture who retreated to an agrarian society a millennia ago when political and social reforms ended wars, famine and ecological disasters; they still shied away from modern technology even after Klingons opened them up to outsiders in 2297.
Their theology held that the reforms were sparked after leaders literally sold out for prosperity by signing a pact with "the devil," Ardra, but aside from considering her name unlucky to speak aloud the people lived uneventfully. They panicked in 2367 when a con artist posing as Ardra returns to claim "her" planet until the U.S.S. Enterprise NCC-1701-D crew successfully revealed her fraud; Captain Picard pointed out that Ardra may likely have been a secret native ruse to help push the reforms. Although agrarian, their capital city still featured tall pyramidal buildings and large public walkways.