We noticed this one near a pool in the Mlilwane Wildlife Sanctuary in Swaziland and we don't have the faintest idea what kind of butterfly it is. I would really appreciate if somebody is willing to tell me how it is called.
Update: It's a Common Sailer "Neptis laeta" (ID with the help from Brian an Steve, thanks guys!)
Canon EOS 5D Mark II, f/8 @ 100 mm (100L IS), 1/250, ISO 400, (cropped)