Dark Sunset

A most unusual sunset. The extra in a black sky, was taken first at a couple of minutes after 5pm and the main photo at 20minutes past 5 pm. It was quite beautiful to watch as it changed.  I noticed in the extra, at the bottom is a streak of red in a white square and am wondering if it is a reflection in a puddle or through my double glazing. The balcony door was open for the main photo.