There is a cave which (was) accessed through a pipe culvert. Due to housing development, it is no longer there. It was a historic record site for cave crayfish and I think cave fish as well. The directions to where the culvert intercepts the cave are accurate, but the bottom of the pipe turns to stone, and it appears the cave was filled in.
This is obviously a horrible idea for many reasons - the selfish reason being "your house may literally cave in" as chucking limestone rock into a solution cave that is carving out limestone is obviously not going to work. In the nearby city there is a law against filling a cave because they learned quickly this is horrible structurally. But this is the county where no such regulations exist.
A classic example of how it may sound good in theory to have fewer regulations and oversight so you can "get shit done easier", but the reality is, regulations are there so you don't fuck shit up. Of course, if one also just ignores rules & regs and does whatever they want to whomever they want, we have a different kind of problem.