Women take a selfie next to a police officer as they take part in New Year's Eve celebrations in the Bund, in Shanghai, China December 31, 2016. (Photo by Aly Song/Reuters)
A man flies a kite on the Bund while buildings of Pudong's Lujiazui financial district stand across the Huangpu River as the sun rises in Shanghai, China, on Friday, October 2, 2015. (Photo by Qilai Shen/Bloomberg)
Dogs wearing masks are seen at a main shopping area, in downtown Shanghai, China, as the country is hit by an outbreak of a new coronavirus, February 16, 2020. (Photo by Aly Song/Reuters)
A little girl wearing a face mask dances in front of a toy panda at a shopping area in Shanghai, following the coronavirus disease (COVID-19) outbreak, China on June 16, 2020. (Photo by Aly Song/Reuters)
A staff member, wearing a face mask following the coronavirus disease (COVID-19) outbreak, looks at a robot at the venue for the World Artificial Intelligence Conference (WAIC) in Shanghai, China on July 9, 2020. (Photo by Aly Song/Reuters)
Cosplayers wearing face masks pose for a picture at the China Digital Entertainment Expo and Conference (ChinaJoy) in Shanghai, following the coronavirus disease (COVID-19) outbreak, China on July 31, 2020. (Photo by Aly Song/Reuters)
A young woman takes pictures of the city with her mobile phone, from the glass-floor observation platform, in the Oriental Pearl Tower, in the financial district of Shanghai, on May 9, 2019. (Photo by Hector Retamal/AFP Photo)
Klemens Torggler's door is an invention based on rotating squares, The special construction makes it possible to move the door sideways without the use of tracks. This technical trick opens up new applications for the door.