They were a religious cult whose founder was named Moon. Here is an excerpt; "The Unification Church of the United States is a new religious movement officially founded in 1954 by Sun Myung Moon (which has led to the referring of his followers as “Moonies”) and moved to America in 1959, where he established his international headquarters."

They are a cult that was founded by the late Sun Myung Moon. The cult became a Unification movement.

They're sort of the classic example (and I mean: THE classic example) of a cult that engages in cult programming of followers (leader claims to be the "Second Coming" of Jesus, religion attracts mostly young adults, followers tend to be obsessively devoted to the point of leaving jobs and family, deprogramming required to extricate followers, etc.) They're (in)famous for mass weddings. Moon would hold "conventions" of sorts, typically in a large sports stadium or other venue that could hold thousands of people simultaneously, and one of the things Moon would do would be to "marry" hundreds or even thousands of couples simultaneously. That is: hundreds or even thousands of people would grab the hand of someone (typically a stranger!) of the opposite sex and come forward. Then Moon would "preside" over a "marriage ceremony" - just one - and then declare all of the couples to be "married". These so-called "Moonie marriages" were sort of notorious for many reasons, but note that Moonie-ism sort of rose up following the end of the Hippie / Free Love movements. That is: it was sort of a successor to those movements. In contrast to those movements, Moonie teachings tended to be extremely conservative, politically speaking: pro-Capitalism and anti-Communism, pro-Nixon, etc.

They also own the conservative "Washington Examiner"

a religious group