Idaho's Silver Valley has produced approximately 1.2 billion ounces of silver since the late 1800s.
The silver output is equivalent to a solid cube as tall as a five-story building.
The region has also yielded significant amounts of lead and zinc.
Briefing: Ancient brines helped build Idaho's Silver Valley and Cobalt belt
Strategic angle: A new study reveals the geological history behind Idaho's Silver Valley, known for its massive silver production.