In Man-Kzin Wars 14 there is a short story entitled "The White Column" by Hal Colebatch. The story describes the last clairvoyant vision of a "far-seer" who was asked to find "the most advanced artifact existing a hundred years from now." The vision produced by the seer was of a white column of unknown scale with tiny figures moving around the base of it. The whole scene in the vision played out somewhere in the Northern hemisphere on Earth, apparently. The story ends with the following enigmatic sentence:
But there had just been time to see the white column, on a soundless beam of light, lift from the ground, turn towards the Pleiades, and vanish.
I've reread the story a few times and have not been able to make any sense of the vision or the ending. The story talks about environmental decay and nuclear proliferation as being future bugaboos forecast earlier by this seer. That along with a reference to Basil Shackleton as another burnt-out seer seems to set the time of the events in the story around 1950-1960. I think that the ending of the story was an allusion to some significant event in the history of Known Space between 1950 and 2050 (otherwise what's the point), but I can't think of anything that fits, except something pedestrian like a traditional rocket launch.
What was the white column and what was it doing?