Russia's President Vladimir Putin and Saudi Arabia's Crown Prince Mohammed bin Salman are seen during the G20 summit in Buenos Aires, Argentina November 30, 2018. G20 powers open two days of summit talks on Friday after a stormy buildup dominated by tensions with Russia and US President Donald Trump's combative stance on trade and climate fears. (Photo by Marcos Brindicci/Reuters)

A jaguar ambushes a giant jacare caiman high up on the Three Brothers River in the Pantanal in Mato Grosso, Brazil. The cat wrestled with the reptile for over twenty minutes in a death struggle witnessed by photographer Chris Brunskill just after ten o'clock in the morning on the 26th of September, 2017. Caimans form a large part of the jaguar's diet in the Pantanal but battles such as this are very rarely observed and seldom photographed. (Photo by Chris Brunskill Ltd/Getty Images)

A man takes a shower on a street from water coming from a drainpipe as it rains in Havana, Cuba, Wednesday, July 27, 2016. During the last couple of weeks short but intense tropical downpours have been coming down of Havana every afternoon. (Photo by Desmond Boylan/AP Photo)

Warriors from the Suri tribe in Ethiopia still stage the savage “Donga” battles – even after many fighters have been died from their injuries. Donga stick fights take place after the harvests, the Surmas count days owing to knots on a long stem of grass or jags on the trunk of a tree dedicated to that specific use. Here: A tribeswoman sporting a huge lip plate and wearing a skinned animal carcass on her head. (Photo by Eric Lafforgue/Exclusivepix Media)

The common brushtail possum (Trichosurus vulpecula, from the Greek for "furry tailed" and the Latin for "little fox", previously in the genus Phalangista) is a nocturnal, semi-arboreal marsupial of the family Phalangeridae, it is native to Australia, and the second largest of the possums.

“Kilauea Rules”. The most extreme place we put ours kayakers to paddle till now. Photo location: Big Island, Hawaii. (Photo and caption by Alexandre Socci/National Geographic Photo Contest)

A large sand sculpture is seen at the site of Yokohama Sand Art Exhibition – Culture City of East Asia 2014 on July 16, 2014 in Yokohama, Japan. Producer and sand sculptor Katsuhiko Chaen invited artists from around the world including South Korea and China, to recreate the World Heritage and historical buildings in China, Japan and South Korea. The exhibition will be open from July 19 to November 3, 2014. (Photo by Chris McGrath/Getty Images)