Coral atolls occasionally develop a short-lived “lagoon cloud” that forms when water evaporates from the relatively warmer central lagoon and the vapor rises and cools. This photo was taken in the Indian Ocean, off Alphonse Island in the Seychelles. The camera was a Nikon D200 with a Nikkor 18-200 mm VR lens at 32 mm. The exposure was f/8 and 1/2000 sec. Image by Irwin H. Segel.