> The Weather Underground Organization (WUO)... was a radical left-wing militant organization founded on the Ann Arbor campus of the University of Michigan ... Weatherman organized in 1969 as a faction of Students for a Democratic Society (SDS).

-- https://en.wikipedia.org/wiki/Weather_Underground

There are a number of books about the group (some by former members) that are worth reading, and there's also a documentary:

-- https://www.imdb.com/title/tt0343168/