Most of Colorado's known natural beauty is due to the fact that the western portion of the state is occupied by the beautiful and majestic Rocky Mountains. The eastern half of the state is largely occupied by prairie, and is fairly flat and unexciting, for the most part. The Pawnee National Grassland, in the northeast corner of the state, however, is quite beautiful. The most well-known feature of this region is the Pawnee Buttes, shown here at sunset.