Formation of a wall cloud or ‘murus’ accessory to the cumulonimbus cloud which is zoomed into by a professional camera. Since the wide photo of the same cloud was completely hidden by cumulus clouds in the foreground, it was difficult to exactly identify the cloud type. However, another photo of the clouds taken before the first thumbnail photo, it looks like the wall came from a distant cumulonimbus calvus cloud as no fibruous or striated parts were visible and was lacking the sharp outlines of the capillatus variety. The murus accessory, seen in the photo as a large and abrupt lowering of the cloud indicated where the strongest updraft was. Instability on that day was produced by an isolated cold pool of air at an altitude of 1500 metres directly overhead the Maltese Islands contrasting with a very warm sea underneath it. The third thumbnail shows what looks like a funnel within the rain-free cloud but which could be part of the murus feature as no rotation was observed. Of note is that the cloud was very distant towards the east of the Maltese Islands making analysis quite difficult. These relate with the cirrus clouds observed here at sunset of the same day and in which the weather conditions are further explained.