I've learned both from others and from experience that the sunset doesn't end when the sun goes down. That was never more true on this particular evening. As the sun sank behind the horizon, its parting rays gave one last gasp of brilliance, lighting up the myriad patterns of high altitude clouds arcing overhead. No photograph could really capture the feeling of seeing it, but I hope this gives you some idea.
Overall, this was one of the best sunsets I've ever experienced in my life. Incidentally, this is actually a multi-shot panorama, stitched together - I had to act fast!