I think the idea is that nobody has any sense, even a very rough one, of how tall the Statue of Liberty might be. It's not like you ever see it in person, and if you did most of it would be in perspective, which ruins your chances of determining its size.
Most people have enough trouble believing that their foot is the same length as their forearm. You never see your feet close up, either.
Most people have enough trouble believing that their foot is the same length as their forearm. You never see your feet close up, either.