A surfer rides a large wave at El Bocal during the Vaca Gigante (Big Cow) giant wave surf competition in Santander, northern Spain December 17, 2016. (Photo by Vincent West/Reuters)

A dog rides a wave during the Surf City Surf Dog competition in Huntington Beach, California, U.S., September 25, 2016. The dogs compete in contest categories ranging from small to extra large, to two dogs on a board, as well as owner and dog. (Photo by Lucy Nicholson/Reuters)

Thousands flock to Bondi Beach for the traditional expats Christmas Day celebration in Sydney, Australia, 25 December 2014. Expats of all nationalities have been flocking to Bondi Beach for Christmas Day for many years. (Photo by Dean Lewins/EPA)

“In honor of Friday’s World Press Freedom Day, the non-governmental organization Reporters sans frontières (Reporters Without Borders) launched a campaign depicting world-famous dictators giving everyone the finger, or the international equivalent thereof”. – Kay Steiger. (Photo by Vincent Bousserez/Reporters Without Borders)

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)

Luke Personius, 12, waits for a wave as he surfs before school at sunrise in Hermosa Beach, California April 2, 2015. The group of friends surf at sunrise most mornings, then shower outside and walk to school. (Photo by Lucy Nicholson/Reuters)

In this April, 2015, photo provided by DC Shoes, daredevil Robbie Maddison in his latest stunt rides his motorcycle across waves in Tahiti, French Polynesia, using ski-like devices on his wheels. (Photo by Tim McKenna/DC Shoes via AP Photo)

A dog catches a wave during the Surf City Surf Dog Contest in Huntington Beach, California September 27, 2015. (Photo by Lucy Nicholson/Reuters)