Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

A fruit importer's lorry at Covent Garden, London, with its driver's cabin in the shape of an apple. (Photo by Harold Clements/London Express/Getty Images). October 1928

A sign is posted in front of the new Yoga Room at San Francisco International Airport's terminal two on January 26, 2012 in San Francisco, California. (Photo by Justin Sullivan/Getty Images)

The crowd watches as stunt pilots Melissa Pemberton, Jurgis Kairys and Skip Stewart of The Immortals fly past pyrotechnics as they perform at The Australian International Airshow on March 1, 2015 in Avalon, Australia. (Photo by Scott E. Barbour/Getty Images)

Purev and Buyantogtokh enjoy the warmth of the fire in the snow in Altai Mountains, Mongolia, September 2016. Navigate the snowy wilds of Mongolia with this nomadic reindeer herding family. Photographer Joel Santos dived 1000km into the depths of Northern Mongolia to visit the Ganbaa family near Khovsgol Lake. (Photo by Joel Santos/Barcroft Images)

Entomologist Anna Platoni wears a hat made of tropical flowers made by florist Emma Reynolds with a Blue Morpho butterfly on her cheek to mark the opening of Butterflies in the Glasshouse at RHS Garden Wisley, south of London, on Janurary 15, 2016. (Photo by Luke MacGregor/PA Wire/RHS)

A woman runs through the early morning mist on Hampstead Heath on September 30, 2011 in London, England. Much of the UK is enjoying a spell of unseasonably hot weather which is expected to last into next week. (Photo by Dan Kitwood/Getty Images)

A man carries a dog and wades through a flooded street in Chennai, in the southern Indian state of Tamil Nadu, Wednesday, December 2, 2015. Weeks of torrential rains have forced the airport in the state capital Chennai to close and have cut off several roads and highways, leaving tens of thousands of people stranded in their homes, government officials said Wednesday. (Photo by AP Photo)