Death Valley, California.
Some years ago, I was coming up out of Death Valley headed towards Soshone, and found a place to stop as the landscape was being lit up by the lowering sun. After the sun actually set , the color deepened on the thin cloud layers, and cast the mountains westward in hues of blue and purple that seemed to glow as the heat rose, to hang in a haze between the ranges. This was one of those sunsets that lingered on and on.
Nikon F5, Nikkor 28-70 f/2.8, Velvia (40), 1.5 seconds @ f/16.