President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

From Britain to China to Mali, new maps showing travel times to the nearest urban centre reveal huge differences between countries. Using Open Street Map and Google, a University of Oxford team have created a visual breakdown that suggests major inequalities when it comes to commuting. Here: China. The dataset used for China was unique as it relied solely on Open Street Map, due to restrictions on accessing Google data. The population is densely concentrated in the east and accessibility is increased, whereas rural provinces in the west remain remote. (Photo by Daniel Weiss/Jennifer Rozier/Malaria Atlas Project/University of Oxford)

Devotees whirl their head as a ritualistic performance during the annual Jhiri Fair at Kanachack village, outskirts of Jammu, India, Monday, November14, 2016. According to the villagers, the fair is held in memory of Baba Jitu, an honest farmer who killed himself since he was not prepared to submit to the unjust demands of a landlord who wanted him to part with his crop. (Photo by Channi Anand/AP Photo)

A man distributes bread to Burka-wearing Afghan women outside a bakery in Kabul, Afghanistan, Thursday, December 2, 2021. According to U.N. figures from early November, almost 24 million people in Afghanistan, around 60% percent of the population, suffer from acute hunger, including 8.7 million living in near famine. Increasing numbers of malnourished children have filled hospital wards. (Photo by Petros Giannakouris/AP Photo)

Britain Athletics, 2016 London Anniversary Games, Queen Elizabeth Olympic Park, Stratford, London on July 23, 2016. Canada's Brent Lakatos crashes with athletes during the mens 1500m T54. (Photo by Eddie Keogh/Reuters/Livepic)

Bronze medalist Carlos Coloma Nicolas of Spain celebrates after finishing third in the cross-country cycling mountain bike race at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Saturday, August 20, 2016. (Photo by Patrick Semansky/AP Photo)

In this October 29, 2013 photo, Daniel smokes marijuana inside his apartment where he uses a hydroponics system to grow his weed in Mexico City. “I'm not a narco, dude. I just like to smoke”, said Daniel, who spoke on condition that his last name not be used because, he said, his home-grow operation is "super-illegal" despite being for personal use only. (Photo by Eduardo Verdugo/AP Photo)