A woman takes part in a four-minute flash mob pillow fight at the Old Town Square in Prague, Czech Republic, December 22, 2016. (Photo by David W. Cerny/Reuters)

Masked revellers pose during the Venice Carnival in Venice, Italy February 11, 2017. The Venice carnival in the historical lagoon city attracts people from around the world. (Photo by Tony Gentile/Reuters)

Christ the Redeemer is seen from the Vista Chinesa (Chinese View) during sunrise in Rio de Janeiro, Brazil, May 4, 2016. Rio de Janeiro is a marvel and a mess all at once. When it hosts the first ever Olympics in South America, starting Aug. 5, visitors will see a city whose stunning topography – stark, verdant mountains loom over packed and playful beaches – competes only with the drama of daily life here. (Photo by Ricardo Moraes/Reuters)

Beltane Fire Society performers celebrate the coming of summer by participating in the Beltane Fire Festival on Calton Hill April 30, 2019 in Edinburgh, Scotland. The event celebrates the ending of winter and is a revival of the ancient Celtic and Pagan festival of Beltane, the Gaelic name for the month of May. This years festival was highlighting climate change, with the central character The May Queen being seen to express her rage at the damage done to Earth. (Photo by Jeff J. Mitchell/Getty Images)

Suzuki's Hanare concept car is displayed during the Tokyo Motor Show, in Tokyo, Japan on October 23, 2019. The 46th Tokyo Motor Show will be op​en​ to the general public from 25 October to 04 November 2019. (Photo by Soe Zeya Tun/Reuters)

A mock-up of a typical British suburban home is seen sinking into the River Thames, in a protest by Extinction Rebellion to demand faster government action on climate change in London, Britain on November 10, 2019. (Photo by Extinction Rebellion/Handout via Reuters)

Tao Xiangli gets out of his homemade submarine after operating it in a lake on the outskirts of Beijing September 3, 2009. Amateur inventor Tao, 34, made a fully functional submarine, which has a periscope, depth control tanks, electric motors, manometer, and two propellers, from old oil barrels and tools which he bought at a second-hand market. He took 2 years to invent and test the submarine which costs 30,000 yuan ($4,385). (Photo by Christina Hu/Reuters)

A female forest guard carries a tranquillizer gun in the Gir National Park and Wildlife Sanctuary in Sasan, in Gujarat December 2, 2014. The sanctuary, which is home to Asiatic lions in India, has an area of 1,412 sq km in which female guards were employed for the first time in India in 2007. The guards fetch a monthly salary of around $148 for working almost 12 hours a day, six days a week, said one of the female guards. (Photo by Anindito Mukherjee/Reuters)