On Friday the 2010 European leg of U2 360° opens at Turin's Stadio Olimpico.
But with just five days to go, a strange light is throbbing in the dark recesses of the stage.
Only those who have seen it before may dare utter its name.
this mystery? (Think you know? Illuminate the rest of us ...
in the comments below.
See all 2010 Tour Countdown Clips
and in Zootopia
check out videos and photos that fans are sharing ahead of the first show.)