what happened here

Without additional context, it is impossible to determine what happened here. The search results include a movie titled "What Happened Here?" which reflects on the tragedy of Leon Trotsky, a blog called "What Happened Here" that explores history, a book titled "What Happened Here" that is a collection of essays by Eliot Weinberger, and two YouTube videos with the same title, one of which is a trailer for a project by Robert Kirkman and the other is a personal essay and "road movie" seeking the site of Leon Trotskys birth and hometown. There is also a video with a transcript that mentions a bunker where something happened, but it is unclear what that event was.