The End is Nigh! (Dark Riders vs X-ers and Avengers)
"We interrupt this regularly scheduled program to bring you this breaking report. It seems like a giant, what can only be called a citadel, rose from the very ground itself and covered almost the entire area of Central Park just moments ago. The monstrosity seems to be composed completely out of stone and there are no discernible entrances. What appears to be people on flying robotic horses circle the citadel. Who built this and to what end has yet to be discovered."