Near the Grand Tetons, the elevation is so high and the sky so wide that it seems like only a small step from a mountain peak into deep space.

This is a good example of what a polarizing filter can do to the sky in the mountains.    The blues of the sky at the horizon give way to a deepening blue - to almost jet black overhead.  I used a wide angle lens and devoted the upper 2/3 of the photo to the sky so the darkening effect would be evident in the setting of the mountains.