The shadow of the earth

I don't know if I've ever seen this phenomenon - probably yes, without realizing what it was.  The phenomenon is explained at APOD:

Explanation: From central Australia, this serene 360 degree panorama follows a clear horizon as twilight began on May 28. At left, a bright western sky is still illuminated by the setting Sun. But sweeping right, toward a view centered on the countryside's dominating sandstone formation called Uluru or Ayers Rock, the sky takes on progressively darker hues and subtle colors. Behind Uluru is the shadow of planet Earth itself, a dark blue arch rising in the east. Cast through the dense atmosphere and still close to the horizon, Earth's long shadow is bounded above by a pinkish glow or antitwilight arch. Known as the Belt of Venus, the lovely color of the antitwilight arch is due to backscattering of reddened light from the setting Sun. On that night, a nearly full Moon also rose above Earth's shadow in the eastern sky.