I'll let others judge the ranked value of this story, found in the short story collection The Book of Sand. Borges himself placed a high value on this story within his oeuvre. "The Congress" is dense with autobiography, clever asides and pet Argentine references. But it also includes wonderful prose and a masterful paragraph on page 38 of the Giovanni translation (E. P. Dutton, 1977.) Beginning with, "I still hold my two images of the ranch . . ." and ending with, ". . . I surprised Irala being watched by an ostrich." this paragraph combines the author's darting, intellectual feints with his economically descriptive observations.
Also, the story suggests to me a resignation: Time wins, memories fade and nostalgia is forbidden.