Giant Mine sits near Yellowknife, in the Northwest Territories of Canada. Once it was a productive gold mine, but after the gold ran out, the mining company went bankrupt and left the government to clean up the mess: enough arsenic trioxide dust to kill everyone on Earth. The solution: freezing it, at least for now.
Thanks to all the team at the Giant Mine Remediation Project! More about them: http://www.aadnc-aandc.gc.ca/eng/1100..
The history of Giant Mine and the local First Nation people, a story I'm not qualified to tell: http://www.cbc.ca/news/canada/north/c..