Clouds gather as walkers pause atop a ridge in Mountain View, California January 7, 2016. (Photo by Noah Berger/Reuters)

Italian Air Force's aerobatic demonstration team, the Frecce Tricolori leave colourful vapour trails as they fly over the Altare della Patria monument on Republic Day (Festa della Repubblica) in Rome, Italy, 02 Jun 2017. The anniversary marks the founding of the Italian Republic in 1946. (Photo by Massimo Percossi/EPA)

Japanese women wearing kimonos take a selfie as they attend their Coming of Age Day celebration ceremony at Toshimaen amusement park in Tokyo, Japan on January 14, 2019. Coming of Age Day is a Japanese holiday held every January to celebrate people who have reached 20 – the official age of adulthood in Japan. (Photo by Issei Kato/Reuters)

Dogs of a visitor pass by the grave of Marquise and Tony, the two small dogs of the Princess Lobanoff de Rostoff at the cimetiere des chiens (Cemetery of dogs) ahead of the commemoration of All Saints Day at the Montmartre cemetery in Asnieres, northern Paris, France, October 30, 2016. (Photo by Charles Platiau/Reuters)

Tomomi Ota pushes a trolley loaded with her humanoid robot Pepper as she crosses a street in Omotesando shopping district in Tokyo, Japan, 24 March 2016. Telecommunications and mobile phone carrier SoftBank Corp. opened a robot-staffed store where 10 Pepper humanoid robots welcome customers looking to buy a mobile phone. The store will be opened until 30 March 2016. (Photo by Franck Robichon/EPA)

A woman walks past servicemen of the self-proclaimed Donetsk People's Republic (DNR), who take part in a rehearsal for the Victory Day parade in Donetsk, Ukraine on May 3, 2018. (Photo by Alexander Ermochenko/Reuters)

A worker carries a basket of fish, at a wholesale fish market, on the outskirts of Kolkata, March 15, 2017. (Photo by Rupak De Chowdhuri/Reuters)

A herd of elephants cross a road that passes through the flooded Kaziranga National Park in the northeastern state of Assam, India, July 12, 2017. (Photo by Anuwar Hazarika/Reuters)