Workers wearing protective suits stand by at a port on April 25 in Yantai, East China’s Shandong province. Photo: VCG

Female workers take a break in a locker room of an electronics factory in 2011 in Dongguan, South China’s Guangdong province. Photo: VCG

Workers operate machines at a factory in China in 1965. Photo: VCG

Chinese workers build the foundations of the ill-fated Yunnan to Burma Railway in 1940. Photo: VCG

Gold miners stand next to a sluice box for collecting gold in California in 1852. Photo: Joseph Blaney Starkweather/VCG

Construction workers eat their lunches atop a steel beam 800 feet above ground at the building site of the Rockefeller Center’s RCA Building in New York City in September 1932. Photo: VCG

Farmers eat lunch in a field during harvest on the Lenin’s Way collective farm in the Soviet village of Vilshanka in 1936. Photo: VCG

A woman collects eggs from chicken in 1941 in Worcestershire, U.K. Photo: VCG

Trainee miners wait underground for a train to take them to a coalface at the Markham Colliery in Derbyshire, U.K., around 1950. Photo: VCG

Women work in the book-keeping room at the Bank of America in Los Angeles around 1970. Photo: VCG