Belt of Venus

The anti-twilight arch or "belt of Venus" is the pink band that you sometimes see across the sky opposite the sunrise or sunset. It is caused by reddened sunlight mingling with the deep blue of the darkened sky. Below it you sometimes see a darker purplish band which is the shadow of the Earth itself on its own atmosphere.

For more information on this atmospheric optical phenomenon follow this link: http://www.atoptics.co.uk/atoptics/earshad.htm