On 8 August, I was flying from Barcelona to Hungary, when I saw a faint pillar of ice crystals glistening close to me outside the window, at right angle to it. The pillar was white and the crystals were so near that I could see them individually. The sun was behind the plane at 54 degs elevation. The display lasted two or three minutes. Ideas of what it could have been are welcome.. Two original photos and their usm-ed versions are attached. Note also the other patch of glistening crystals to the left of the pillar ( 1 - 2 - 3 - 4 ).