Photographer David Emitt Adams creates tintypes on discarded cans he collects from the Sonoran Desert. In his artist statement, Adams says that some are more than four decades old, which have earned a deep reddish-brown, rusty coloration. (Photo by David Emitt Adams)

Beyonce Knowles attends the “Schiaparelli And Prada: Impossible Conversations” Costume Institute Gala at the Metropolitan Museum of Art on May 7, 2012 in New York City. (Photo by Randy Brooke)

Kim Kardashian west and Madonna backstage at MDNA SKIN hosts Madonna and Kim Kardashian West for a beauty conversation at YouTube Space LA on March 6, 2018 in Los Angeles, California. (Photo by Kevin Mazur/Getty Images for Madonna's MDNA SKIN)

Humanoid robot bartender “Carl” interacts with guests at the Robots Bar and Lounge in the eastern German town of Ilmenau, July 26, 2013. “Carl”, developed and built by mechatronics engineer Ben Schaefer who runs a company for humanoid robots, prepares spirits for the mixing of cocktails and is able to interact with customers in small conversations. (Photo by Fabrizio Bensch/Reuters)

Indonesian mahouts clean their Sumatran elephant in a river near the zoo in Medan, North Sumatra, Indonesia, 12 December 2014. According media reports, the smallest of the Asian elephants, Sumatran elephant (Elephas maximus sumatrensis) is facing serious pressures arising from illegal logging and associated habitat loss and fragmentation in Indonesia. The population has come under increasing threat from rapid forest conversion to plantations. (Photo by Dedi Sahputra/EPA)

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)

A woman plays around as she walks across a glass-bottomed suspension bridge in a scenic zone in Pingjiang county in southern China's Hunan province Thursday, September 24, 2015. The bridge, 300 meters (984 feet) long and 180 meters (590 feet), opened to visitors on Thursday for the first time since its conversion from a regular suspension bridge was completed. (Photo by Chinatopix Via AP Photo)

“If a man insisted always on being serious, and never allowed himself a bit of fun and relaxation, he would go mad or become unstable without knowing it”. – Herodotus. “You can discover more about a person in an hour of play than in a year of conversation”. – Plato. Photo: Mandalay, Burma. (Photo by Steve McCurry)