Workers walk between brine pools that are part of the lithium pilot plant on the Uyuni salt lake in southwestern Bolivia

Workers walk between brine pools that are part of the lithium pilot plant on the Uyuni salt lake, which holds the world’s largest reserve of lithium, located at 3,656 meters (11,995 ft) above sea level in southwestern Bolivia, November 5, 2012. REUTERS/David Mercado (BOLIVIA)

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