Marchers walk from the University of Mississippi in Oxford, Miss., on Saturday, April 22, 2017. Bruce Newman/The Oxford Eagle via APJill Johnson and Kerry Lannert prepare a sign prior to the March for Science at Cal Anderson Park in Seattle.Getty ImagesRetired U.S. Army Corporal Amy Schienschang from Williamsburg, Va., in Washington, D.C. Sait Serkan Gurbuz/ASSOCIATED PRESSSupporters of science and research gathered in Amsterdam. ROBIN UTRECHT/EPAThe Stasiak family arrives to the Washington Monument before attending the Washington, D.C., rally and march. Mark Makela/NYTPeople line the sidewalk in Central Park listening to speakers before marching in New York City.Bryan R. Smith/AFP/Getty ImagesDemonstrators walked down Broadway in New York. Bryan R. Smith/AFP/Getty ImagesCaroline Starboard holds an American flag as she waits to join a long line of protesters in Denver. David Zalubowski/APMassachusetts General Hospital’s March For Science heads towards the Boston Common. Jonathan Wiggs/The Boston GlobeA group from Massachusetts General Hospital heads toward the Boston Common.Jonathan Wiggs/The Boston GlobeStephanie Woodend and and Abby Dalton at the march in Ottawa, Canada.Justin Tang/The Canadian Press via APA person held up a sign that reads “Fund Climate Change Research / Saving The Planet Is Not A Waste Of Money.” Sait Serkan Gurbuz/APErin Greeson from the Planetary Society spoke with Bill Nye “The Science Guy” backstage in Washington, D.C. Sait Serkan Gurbuz/APProtesters held banners during Madrid’s march.Daniel Ochoa de Olza/APPeople stood together holding placards during the March for Science in Geneva, Switzerland.Martial Trezzini/Keystone via APDozens of Sitkans dressed as their favorite animals march in the annual Parade of Species in Sitka, Alaska, on April 21, 2017. This year the parade merged with the worldwide science marches. JJames Poulson /The Daily Sitka Sentinel via APScience supporters in Parliament Square, London.APDemonstrators pose while holding a placard in London.AFP/Getty Images