A station of the U.N. peacekeeping forces in Lebanon, in Markaba, near the border with Israel, last year.

Chuck Searcy, 79, co-founder of a group that works to deactivate unexploded bombs in Vietnam, a legacy of the war. He stood next to deactivated ordnance in Dong Ha City, Quang Tri Province, last month.

A nickel processing plant in Sulawesi. Indonesia has vast supplies of nickel, which is critical to battery manufacturing.

An artisanal gold miner working in Kalana, Mali, in 2012. Artisanal mining has provided a livelihood for thousands of people in several West African countries over the past two decades.

Only about 1 percent of rare earth metals in old electronic products are currently reused or recycled, researchers estimate.

New technology from a company called ShieldAI creates drones that work in tandem through artificial intelligence. The company is working with the Defense Department, but does not have armed drones at this point.

The innards of a catalytic converter are coated in some of the rarest, most expensive metals on the planet.

The innards of a catalytic converter are coated in some of the rarest, most expensive metals on the planet.