People sit around a fountain at Trafalgar Square in London, Britain, on May 17, 2020. (Photo by Tim Ireland/Xinhua)

Visitors line up to enter Galleria Borghese in Rome, Italy, May 20, 2020. (Xinhua/Cheng Tingting)

People enjoy leisure on the banks of the Seine in Paris, France, on May 17, 2020. (Photo by Aurelien Morissard/Xinhua)

An operator modifies the circulation of vehicles to widen the sidewalks and ensure social distancing on pedestrians in Barcelona, Spain, May 19, 2020.(Barcelona City Hall/Handout via Xinhua)