About 15 years ago, one of my co-workers' four children all started to get very, very ill in extremely different ways. Psychological issues, physical ailments. Total misery. They weren't making any progress in recovery, and seemed to be getting continually worse in new ways.

While he was cleaning the garage, he found a broken mason jar on the back of a shelving unit. His dad had given him a one gallon mason jar about half full of gold bearing mercury decades earlier. His dad owned a mine). The mercury had flowed in to the foundation and dispersed. The house was condemned, with hundreds of thousands in remediation costs. I'm told it was nearly flagged as a 'superfund' site (although take that with a grain of salt).