A robin perches on a spade handle in a garden on a rainy day in Lixwm, north Wales. Researchers said this week that when European robins are subjected to human-produced noise, their behaviour changes. (Photo by DGDImages/Alamy Live News)

A 180 degrees rotated photograph shows the shadows of Polina (L), a six-year-old Belarusian first grade school girl, and her father, cast on the street while on their way to Polina's first day of school, which marks the traditional start of the academic year, in Minsk, Belarus, 02 September 2019. The start of a new academic year in Belarus, officially called Day of Knowledge, is a festive day for all school and university students in the country. (Photo by Tatyana Zenkovich/EPA/EFE)

A view through mist shows the Kirk of Saint Mary Magdalene in Primorsk, Leningrad Region, Russia on March 24, 2019. (Photo by Anton Vaganov/Reuters)

Hundreds of pumpkins lie on a field near Frankfurt, Germany, after sunset on Wednesday, October 16, 2019. The autumn vegetable heralds the approach of halloween. (Photo by Michael Probst/AP Photo)

Fans of the Kansas City Chiefs pose for photos before the game against the Los Angeles Chargers at Estadio Azteca on November 18, 2019 in Mexico City, Mexico. (Photo by Manuel Velasquez/Getty Images)

Fifty years ago, as France exploded in mass protests, words scrawled on the walls of the Sorbonne summed up the revolutionary zeal of the time: “Run free, comrade, we’ve left the old world behind!”. Sexual liberation, artistic creativity and anti-capitalism were the order of the day. For those who were there, it was an unforgettable time. Here: A wounded student is transported by first-aid workers during riots on the Boulevard Saint-Michel, Paris, France on May 6, 1968. (Photo by Gökşin Sipahioğlu/SIPA Press)

Cha Huilan, a 40-year old Lisu woman, and her daughter leave Lazimi village with a zipline across the Nu River in Nujiang Lisu Autonomous Prefecture in Yunnan province, China, March 24, 2018. Chinese mountain villagers, cut off from shops and churches by a raging river, use a zipline to cross its violent rapids and jagged rocks. (Photo by Aly Song/Reuters)

Democratic Congressional candidate Alexandria Ocasio-Cortez poses with a campaign worker during a whistle stop in Queens, New York, November 5, 2018. (Photo by Andrew Kelly/Reuters)