I was at job driving my van towards a long straight road in Bologna, the city where i live.I was looking ahead on the traffic when i saw brilliant light in the sky in front of me.The light was yellow/orange and seemed quite hot,just like a little sun; it was also sorrounded by a beautiful little rainbow on its lower part. Either the light and the rainbow were very clear in the sky. Although the day was quiet cloudy. Right after this,i also noticed a huge disc-shaped object floating steady just on the left of the light. The "object" seemed to me like disguised as a cloud; it was like a disc shaped cloud of a totally different color than its sorroundings. It was light grey/silver/white,quite bright,but the whole sky around was cloudy grey or clean.