New article in REALTOR.com (w/55 million unique visitors) live links to InterNACHI.

[gromicko (Nick Gromicko, CMI)]

What Is a Sinkhole? A Scary Threat That's Rare, but All Too Real

[rlewis5 (Roy Lewis, CERTIFIED MASTER INSPECTOR RETIRED)]

That depends on where you live.
We have hundreds on old sink holes around my neck of the woods.
The cave system goes underneath most of my side of the county.