Sink Holes! And Weathering!

Have you noticed the increased press coverage about Sink Holes lately? 

"Suddenly, it seemed that sinkholes were popping up, or down, on a daily basis.... According to geologists, this is because sinkholes have opened up on a daily basis for as long as anyone can remember. The difference is that nobody paid them much heed until now." 

"... there are sinkholes, and then there are man-made sinkholes. Real sinkholes occur when rain naturally transformed into weak carbonic acid eats away particularly susceptible underground rock like limestone or gypsum — also known as karst — creating underground holes"  

This is a great example of chemical weathering on a large scale!