Elephant at sunset feeding on the grasses by the Chobe River, Chobe National Park, Botswana
The blue line in the sky is a good example of the atmospheric phenomenon known as the Belt of Venus (or Venus' Girdle), where the earth's shadow can been seen in the sky opposite the sunset. Often the best and most subtle colors at sunset and sunrise can be found in the sky opposite the sun.
My big computer has packed it in (they are sending a free replacement), so I am featuring some photos from a gallery of photos taken this past summer in Botswana. Chobe National Park is famous for its large populations of elephants.