Elephants cool off at a zoo in Karachi, Pakistan, 31 March 2021. Caretakers at Karachi's zoo were working to keep animals cool during a heatwave affecting southern Pakistan. (Photo by Shahzaib Akber/EPA/EFE)

Mozambique army soldiers take a ride on a motorbike in the streets of Palma, Cabo Delgado, Mozambique, 12 April 2021. The violence unleashed more than three years ago in Cabo Delgado province escalated again about two weeks ago, when armed groups first attacked the town of Palma. (Photo by Joao Relvas/EPA/EFE)

Revellers make the most of Boxing Day in Liverpool city centre, United Kingdom on Sunday, December 26, 2021. Boxing Day is a holiday celebrated after Christmas Day, occurring on the second day of Christmastide. (Photo by London News Pictures)

Divers wearing mermaid costumes take part in the first Chinese Mermaid Performance Contest at Atlantis resort on December 21, 2021 in Sanya, Hainan Province of China. (Photo by Luo Yunfei/China News Service via Getty Images)

Revellers take part in the Els Enfarinats festival, in the town of Ibi near Alicante, Spain, Tuesday December 28, 2021. For about 200-years the inhabitants of Ibi annually celebrate with a battle using flour, eggs and firecrackers, outside the city town hall. (Photo by Alberto Saiz/AP Photo)

An overcrowded dinghy with migrants from different African countries is followed by members of the German NGO Jugend Rettet as they approach the Iuventa vessel during a rescue operation, off the Libyan coast in the Mediterranean Sea September 21, 2016. (Photo by Zohra Bensemra/Reuters)

A group of people are seen on a Victoria line train in London, England during the first night of the Night Tube service on August 19 2016. The Central line and Victoria line are the first to operate a Night service with further lines expected to be running by the end of the year. (Photo by SWNS.com)

Robot inventor Wu Yulu sits on a rickshaw driven by a robot which he invented in his village in rural Beijing's Tongzhou district, China, 17 November 2016. The 54-year-old Chinese farmer living in rural Beijing's Tongzhou district invented 63 robots in the past 30 years. Wu, who only received primary school education, plans to give up the agricultural work for his robot products. He regularly participates in exhibitions, transfers patent rights and teaches at the university to earn money. (Photo by Wu Hong/EPA)