"Tower of Babylon" by Ted Chiang. It's a novelette that's part of his compilation "Stories of Your Life and Others". To quote Wikipedia, "the story follows a young miner from the town of Elam who ascends the tower of Babylon to help break through the vault of heaven. Along the way he sees many wonderous sights, uncovers mysteries of heaven and earth, and in the end finds them as inscrutable as ever."