Oh...
that. That actually is just some spotlight objects I placed onto the central tower roof. The beams of light they emit were pretty neat, so I figure I'd put them up there.
Also, if you look close enough, I put cannons on top of the other towers and had them pointing away from the center. That, and I'm also proud of the stone dragon statue on the fountain in the center, too.
I'm still looking for the .a2w file. I'm fairly sure I lost it, but it's possible I may have hid it in one of my older files.... maybe I'll ask Bob...