In this September 17, 2010 file photo a little brown bat is photographed in La Crosse Wis. Researchers for the first time found that little brown bats appear to be showing resistance to white-nose syndrome, which has killed millions of bats across North America. (Photo by Peter Thomson/La Crosse Tribune via AP Photo)

People wear clothing to protect them from the heat while riding along a street in Hanoi, Vietnam, 24 April 2019. North and central Vietnam was recently affected by extreme hot weather, with the highest temperatures reaching over 40 degrees Celcius, according to the National Centre for Hydro-meteorological Forecasting. (Photo by Luong Thai Linh/EPA/EFE)

Men push a car stucking in the mud on a motorway in Nimba County, Liberia, 28 July 2019. Most highway roads in the rural parts of the country are unpaved. The government of President George Weah has promised to build roads to connect all big cites of Liberia. (Photo by Ahmed Jallanzo/EPA/EFE)

Two and a half year-old Jennifer Martin in tears during a visit to Santa at Harrods department store in London, 10th December 1949. (Photo by William Vanderson/Fox Photos/Hulton Archive/Getty Images)

An Army Sikorsky R-5 helicopter, undergoing record trials, demonstrates its lifting power by carrying 17 persons and pilot aloft as female onlookers wave in Bridgeport, Conn., January 10, 1946. During the tests records were claimed for altitude speed and both altitude and speed with payload. (Photo by Anthony Camerano/AP Photo)

British housewives toss pancakes in skillets as they run through the streets of Olney, England, in the community's annual race which follows a 500-year-old tradition, February 6, 1951. Mrs. Isabel Dix, 22, extreme right, won the race covering the 415 yards from the Parish pump to the door of Sts. Peter and Paul church in one minute, 12.1 seconds. (Photo by AP Photo)

Tourists pose for a selfie in Cancun, October 13, 2015. Cancun's transformation in the 1970s from a small Caribbean fishing village into a strip of nightclubs and high-rise hotels has reduced biodiversity and polluted water resources as infrastructure struggles to keep up. (Photo by Edgard Garrido/Reuters)

A paper rhacophorus arvalis (farmland green tree frog) of Taiwan (R) is surrounded by paper pandas at an exhibition called “Pandas on Tour” at the National Theater in Taipei on February 24, 2014. Some 1,600 paper made pandas are on display, designed by French artist Paulo Grangeon. (Photo by Mandy Cheng/AFP Photo)