In this November 28, 1966 file photo, one of the 10 beagles involved in the first test of the Veterans Administration Hospital in East Orange, N.J. smokes a cigarette through a machine linked to its windpipe by a plastic tube to test any link between smoking and emphysema. (Photo by AP Photo)

A visitor passes behind the sculpture “Puma-Dentist” made with plastic, wax and original heads of a puma and a hind by Austrian artist Deborah Sengl during an exhibition at the art gallery Deschler in Berlin April 15, 2008. (Photo by Fabrizio Bensch/Reuters)

A niqab-wearing Salafist protester takes a selfie as she attends a demonstration against the ban on the sale and manufacturing of the full-burqa in Rabat January 15, 2017. (Photo by Reuters/Stringer)

A man with a mask poses for a portrait as he takes part in festivities in honour of patron saint San Jeronimo in Masaya city, Nicaragua November 20, 2016. (Photo by Oswaldo Rivas/Reuters)

A man takes a dip inside a chapel during celebrations of the Orthodox Christian feast of Epiphany in Saint Petersburg, Russia on January 19, 2020. (Photo by Anton Vaganov/Reuters)

Internally displaced Syrian children who fled Raqqa city stand near their tent in Ras al-Ain province, Syria January 22, 2017. (Photo by Rodi Said/Reuters)

Long-tailed mayflies (Palingenia longicauda) at Tisza river near Tiszainoka 135km (84 miles) southeast of Budapest, June 23, 2013. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/Reuters)