Oklahoma City bombing
The Oklahoma City bombing (sometimes abbreviated as OKC or OKC Bombing) was a domestic terror attack carried out against a Federal Government building in 1995. It's the deadliest domestic terror attack in US history, and the second deadliest US terror attack after 9/11.
The perpetrators of the bombing were closely tied to the militia movement, and the bombing itself bears close resemblance to parts of The Turner Diaries (one of the perpetrators had photocopies of pages from The Turner Diaries on their person when he was arrested).
The event had major ramifications for for right movements in the US, particularly militia adjacent movements. Despite various attempts to paint the event as a false flag, it generally turned mainstream public opinion against related far-right movements, and caused the government to take a more critical and active view of far right extremism. In aggregate, militia groups saw substantial setbacks during the late 90s and early 2000s[1], and only really regained prominence in the 2010s.