Couples take part in a Valentine's Day attempt to break the record for the world's largest simultaneous gay kiss on February 14, 2004 in Rome, Italy. (Photo by Franco Origlia/Getty Images)

Couples take part in the “Love and Challenge Marathon” in Hanoi, Vietnam, 16 August 2015. Fifty couples, who are going to get married, participated in the event which is held the fifth time. This year, the winners of the marathon received a honeymoon trip to Malaysia. (Photo by Luong Thai Linh/EPA)

“Sniff out the Appenzell Cheese”. Alexander Hunter, 30, of Greenwich, Conn., took this photo in Appenzell, Switzerland, in September 2014. (Photo by Alexander Hunter)

Doris Dean of Chicago, Ill., sits with her gun shortly after she won a 50 meter, 40-shot event for women with a perfect 400 score at the National Rifle Association (NRA) matches at Camp Perry, near Toledo, Ohio, September 7, 1941. (Photo by AP Photo/DW)

North Koreans wave as Hughes MD-500 helicopters fly past during an aerial display on Saturday, September 24, 2016, in Wonsan, North Korea. North Korea on Saturday opened an air festival featuring sky diving, demonstrations by its air force and lots of beer to promote a newly renovated and upgraded commercial airport in the coastal city of Wonsan that it hopes will draw for foreign tourists. (Photo by Wong Maye-E/AP Photo)

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)

Girls prepare to take part in a mermaid lesson in Rio de Janeiro, Brazil May 28, 2017. Women in Brazil are not unique in their affinity for mermaiding. Classes are held as far away as Texas and some folks wonder if mermaiding will be the next fitness craze. (Photo by Pilar Olivares/Reuters)

A Highland Cow at sunset on the edge of the Marlborough Downs, Wiltshire, United Kingdom on October 18, 2020. (Photo by David White/PictureExclusive)