A man drinks at a "colored" water cooler in a streetcar terminal in Oklahoma City, July 1939. (Photo by Reuters/Library of Congress)

A U.S. Marine leads training on a shooting range in France in an undated photo taken during the First World War. (Photo by Reuters/Courtesy Library of Congress)

South Asian countries in terms of total contribution of travel and tourism to GDP. #6. Vietnam, Total GDP: USD 202.6 billion (2016). Contribution of Travel and Tourism to GDP: 9.1% . Here: A boat in the Thu Bon River, Hoi An, Vietnam. (Photo by Domingo Leiva/Getty Images)

Peasants in the re-taken Somme District work in the fields, circa 1916- 1917, in this Library of Congress handout photo. For women 100 years ago, opportunities to work beyond the home and take part in political life were very limited. As the 20th century progressed, hard-won progress included gradually improved voting rights, while the upheaval of war pushed doors ajar as women worked as part of the war effort. U.S. Library of Congress archive photos show women's workplaces ranging from a flour mill in England to a coal mine in Belgium or Lincoln Motor Co.'s welding department in Detroit. International Women's Day is celebrated on March 8. (Photo by Reuters/Bain Collection/Library of Congress)

A visitor kneels down nex to an iCub robot made by the Italian Institute of Technology at the scientists congress IROS 2015 in Hamburg, Germany October 2, 2015. The robot congress is organized by TAMS group (Technical Aspects of Multimodal Systems) of Hamburg's university. (Photo by Fabian Bimmer/Reuters)

Hotel ushers pose for a photo at Tiananmen Square as delegates attend the second plenary session of the National People's Congress (NPC) in Beijing, China, March 9, 2018. The CPPCC is the top advisory body of the Chinese political system and runs alongside the annual plenary meetings of the 13th National People's Congress (NPC), together known as “Lianghui” or “Two Meetings”. (Photo by Jason Lee/Reuters)

Sellers sort persimmons for sale at a wholesale market in Hanoi, Vietnam October 3, 2016. (Photo by Reuters/Kham)

A Vietnamese bride is seen pushing the groom on a scooter during a photo shoot for their wedding in An Bang Beach outside Hoi An in Vietnam December 11, 2016. (Photo by Reuters/Stringer)