The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)

Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)

Boys in ceremonial uniform at the civil wedding ceremony of American actress Grace Kelly and Rainier III, Prince of Monaco at the Prince's Palace of Monaco, 18th April 1956. Original publication: Picture Post - 8336 - The Hour Of Marriage - pub. 28th April 1956.

Members of the Knights Guard clean the ice during the Vegas Golden Knights' game against the Anaheim Ducks at T-Mobile Arena on January 14, 2021 in Las Vegas, Nevada. The Golden Knights defeated the Ducks 5-2. (Photo by Ethan Miller/Getty images/Profimedia)

A fan runs on the field during the fourth quarter of Super Bowl LV between the Tampa Bay Buccaneers and the Kansas City Chiefs at Raymond James Stadium on February 07, 2021 in Tampa, Florida. (Photo by Mike Ehrmann/Getty Images)

Femen activists with their bare chests reading “Fascists out of ballot boxes” are held back by Catalan regional police forces Mossos d'Esquadra as they protest against far-right Vox party candidates in Barcelona during regional elections in Catalonia on February 14, 2021. Catalonia is voting in an election overshadowed by the pandemic which Madrid hopes will unseat the region's ruling separatists more than three years after a failed bid to break away from Spain. (Photo by Lluis Gene/AFP Photo/Profimedia)

A bandana-clad anti-government demonstrator gestures as she stands by the smoke of burning tires at a make-shift roadblock in Zouk Mosbeh north of Lebanon's capital Beirut, on March 8, 2021 during a protest against the deteriorating value of the local currency and dire economic and social conditions. (Photo by Joseph Eid/AFP Photo)

Visitors wear masks as they catch some shade under the Oscar Mayer Wienermobile amid 50 acres of Ranunculus flowers at “The Flower Fields” in Carlsbad, California, U.S., March 31, 2021. (Photo by Mike Blake/Reuters)