Some of these are immense! From the <a href="https://www.facebook.com/KansasGeologicalSurvey/">Kansas Geological Survey</a> Facebook page:

<p>Some of these are immense! From the <a href="https://www.facebook.com/KansasGeologicalSurvey/">Kansas Geological Survey</a> Facebook page:</p><div><iframe src="https://www.facebook.com/plugins/post.php?href=https%3A%2F%2Fwww.facebook.com%2FKansasGeologicalSurvey%2Fposts%2F2857183304335717&width=500" width="500" height="774" style="border:none;overflow:hidden" scrolling="no" frameborder="0" allowTransparency="true" allow="encrypted-media"></iframe></div>

KGS offers information about sinkholes