The Ligghtning struck tower.
Now I don't know about any other HP fans, but the Dark Mark they've done for the movies sucks IMO. The design I've done is probably one of the oldest ideas I've had on the back burner. I'd say since either 00 01(I got into HP a year after GoF was out). And I've wanted to design the Dark Mark since then. I'll have a hard time converting that into the green sky version but hopefully it'll be okay.