Musician Simon Desorgher walks his giant sphere on the foreshore of the River Thames after a rehearsal for a performance of “Water Cycle for flute and sound system” on the river on September 11, 2009 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A man walks past specially designed wash basins in a public toilet at the Foreigners Street on April 26, 2007 in Chongqing Municipality, China. (Photo by China Photos/Getty Images)

A model walks the runway at the Iris Van Herpen Haute Couture autumn winter 2011 fashion show during Paris Haute Couture Week on July 4, 2011 in Paris, France. (Photo by Nathalie Lagneau/Catwalking/Getty Images)

Models walks the runway at the Stephan Pelger Show during Mercedes-Benz Fashion Week Berlin Spring/Summer 2012 at the Brandenburg Gate on July 9, 2011 in Berlin, Germany. (Photo by Gareth Cattermole/Getty Images for IMG)

Kate Upton walks the runway at the Beach Bunny Swimwear show during Merecdes-Benz Fashion Week Swim 2012 at The Raleigh on July 15, 2011 in Miami Beach, Florida. (Photo by Frazer Harrison/Getty Images for Beach Bunny)

A Thai woman walks through the deep flooded streets October 21, 2011 in Pathumthani on the outskirts of Bangkok, Thailand. (Photo by Paula Bronstein/Getty Images)

A model wearing a Maxime Rappaz design, winner of the Annabelle Award, walks the runway during the second day of the Charles Voegele Fashion Days on November 10, 2011 in Zurich, Switzerland. (Photo by The Image Gate/Getty Images for IMG)

Boys walk home for lunch from school in the village of Kogelo, west of Kenya's capital Nairobi, July 16, 2015. U.S. President Barack Obama visits Kenya and Ethiopia later this month. His ancestral home of Kogelo is home to Sarah Hussein Obama, his step-grandmother. The Kenyan village, burial place of Obama's father, features an open-pit goldmine, a pork butcher's, a school named after their most famous son and outdoor market stalls. Villagers get around by motorbike taxi or on foot while a donkey-cart transports water. Children, some of them named Obama in honour of the President, walk to and from school together. (Photo by Thomas Mukoya/Reuters)