Seven-year-old Mimi Meade winces from the sting as Dr. Richard Mulvaney inoculates her April 26, 1954 in McClean, Va., with the new Salk polio vaccine. Mrs. John Lucas, a registered nurse, holds Mimi's arm steady as she gets one of the first injections of the countrywide test. (Photo by Harvey Georges/AP Photo)

A devotee pulls a chariot during the Hindu festival of Thaipusam in Singapore February 9, 2017. (Photo by Edgar Su/Reuters)

Nikolay Skidan, a hunter, carries the skin of a wolf in the village of Khrapkovo, Belarus February 1, 2017. Wolf fur grows thickest in winter, so Belarussian hunter Vladimir Krivenchik only sets his traps once snow is on the ground. He and his wife live on the edge of the Chernobyl exclusion zone – 2,600 square km of land on the Belarus-Ukraine border that was contaminated by a nuclear disaster in 1986. (Photo by Vasily Fedosenko/Reuters)

Bikini Contest in Daytona Beach, Florida, USA. (Photo by Evan Hurd/Sygma/Sygma via Getty Images)

Two holidaymakers amuse themselves with a porter's trolley whilst waiting for their train at Euston Station, London, 5th August 1939. (Photo by A. J. O'Brien/Fox Photos/Getty Images)

Models struggle against strong wind before the rehearsal of Christian Dior's Haute Couture Spring-Summer 2017 live show to celebrate Dior's new flagship store at the rooftop of Ginza Six mall in Tokyo, Japan, April 19, 2017. (Photo by Toru Hanai/Reuters)

In this June 29, 2016 file photo, boats docked at Central Marine in Stuart, Fla., are surrounded by blue green algae. The 153-mile-long Indian River Lagoon has been plagued by harmful algae blooms. Water quality testing data analyzed by the AP showed the average phosphorous level – a byproduct of fertilizers and human waste that algae thrive on, rose nearly 75 percent between 2000 and 2016. (Photo by Greg Lovett/The Palm Beach Post via AP Photo)

In this Thursday, February 14, 2019, photo, a Transformer's Bumblebee mascot helps a woman carries paper bags at a shopping mall in Handan in north China's Hebei province. U.S. and Chinese envoys are holding a second day of trade talks after the top economic adviser to President Donald Trump said he has yet to decide whether to go ahead with a March 2 tariff increase on imports from China. (Photo by Chinatopix via AP Photo)