After a recent night flight I was chatting with pax just after landing, discussing what a beautiful night-sky we have just seen, full moon and planet Venus shining beautifully, etc. I was telling then about storms, the Noethern Lights etc that I have seen in the past from the cockpit when flying at night. So I asked them if there is any natural pheniomena they have seen. After thinking about it for a moment, the lady said "Well, yes, the Taj Mahal" !