Giving out with a yell, Elke Sommer is tossed on the trampoline as she trains for her movie role as an athlete, on the playing field of the University of California at Los Angeles, June 8, 1967. (Photo by AP Photo)

Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

Riot police clash with demonstrators protesting against proposed pension reforms outside the Congress in Buenos Aires on December 18, 2017. Protesters angry at proposed pension and welfare reforms attacked police close to Argentina's congress building in Buenos Aires on Monday, the second protest in a week to turn violent. Activists lobbed stones, bottles and firecrackers at police as huge crowds demonstrated against pension reforms proposed by the center-right government of President Mauricio Macri. (Photo by Eitan Abramovich/AFP Photo)

Russian cadets march during the annual cadet schools get-together in Moscow, Russia on March 30, 2018. (Photo by Mladen Antonov/AFP Photo)

Villagers from Jiexi Jiantan village perform a ritual of “Zha Laoye”, or “Cracking local spirits”, in Chaoshan, Guangdong Province, China, 10 February 2019. Jiexi Jiantan Village celebrates the annual custom of “Zha Laoye” where Laoye are local spirits. Every third day of the lunar New Year, statues of local spirits known as the “Thousand-mile Eye” Laoye and “Ear Following the Wind” Laoye are brought out to the village committee to receive incensed tea offered by believers. (Photo by EPA/EFE/ZNSEN)

Brazilian actress Julia Stockler (L) and Brazilian actress Carol Duarte kiss while posing with Brazilian film director Karim Ainouz during a photocall for the film “A Vida Invisivel de Euridice Gusmao (The Invisible Life of Euridice Gusmao)” at the 72nd edition of the Cannes Film Festival in Cannes, southern France, on May 20, 2019. (Photo by Stephane Mahe/Reuters)

A Monster Jam truck performs a back flip during the first-ever monster truck event in Beijing's iconic “Bird's Nest” National Stadium on Saturday, July 29, 2017. (Photo by Ng Han Guan/AP Photo)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)