Chinese aids activists hand out condoms in a subway train in Wuhan, central China's Hubei province on December 1, 2014. The World Health Organization issued a call to action to China on December 1, 2014 over HIV/AIDS as government figures said nearly half a million people are living with the disease or its precursor, with hundreds of thousands more thought to be undiagnosed. (Photo by AFP Photo)

Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

Yaroslav Segeda at the top of a high rise building in Kudrinskaya Square, Moscow, Russia. (Photo by Yaroslav Segeda/Caters News)

A shop assistant creates a window display in a Next store in central London December 30, 2014. British clothing retailer Next's sales rose 2.9 percent in the run up to Christmas mostly due to online and catalogue purchases, hitting the upper end of its predictions and it said full-year profit would rise by about 11.5 percent. (Photo by Neil Hall/Reuters)

A woman walks against blowing snow in Evanston, Illinois, on February 8, 2014. (Photo by Nam Y. Huh/Associated Press)

A ring-tailed lemur is pictured at Zoom Torino, a zoological park in Cumiana near Turin, on April 22, 2015. Zoom Torino is a new immersive zoological park, where animals can be seen without bars or cages, only natural barriers ensure the visit. (Photo by Marco Bertorello/AFP Photo)

Participants lay down on a street covered by coloured powder during the annual Bangkok Color Run in Bangkok, Thailand April 1, 2017. (Photo by Athit Perawongmetha/Reuters)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)