"In assuming that it was very tall, you are relying on an obsolete reading. The tower is described, literally, as ‘its top with the heavens.' For many centuries, this was interpreted to mean that its top was so high that it was in the heavens. But in the last century or so, as actual Babylonian ziggurats have been excavated, astrological diagrams—pictures of the heavens—have been found inscribed into their tops."