Ironically, the site would probably say you can see 20 km from inside the basement.
What's ironic about that? Of course it would. It's working off of large-scale terrain features, not structures. It will also tell you that you can see distant mountains when it's cloudy or you don't have your glasses on.
What's ironic about that? Of course it would. It's working off of large-scale terrain features, not structures. It will also tell you that you can see distant mountains when it's cloudy or you don't have your glasses on.