Last weekend, the National Building Museum in Washington, D.C., opened a 10,000 square-foot ball pit to the general public, and everyone cheered that, finally, someone made their childhood dreams come true.

Fuse TV VJ's Marianela and Juliya attend the store opening of “Nigo's A Bathing Ape” with Pharrell Williams January 11, 2005 in New York City. (Photo by Paul Hawthorne/Getty Images)

Paris Saint-Germain's Italian goalkeeper #01 Gianluigi Donnarumma and Salzburg's Serbian forward #21 Petar Ratkov vie for the ball during the UEFA Champions League football match between FC RB Salzburg and Paris Saint-Germain in Salzburg, Austria on December 10, 2024. (Photo by Franck Fife/AFP Photo)

Some are in it just for the money, others to help buy a meal. Then there are those who trade for fun or to spend time among friends. Millions of investors – pensioners, security guards, high-school students – dominate China's stock markets, conducting about 80 percent of all trades. Retirees gather in brokerage houses dotted around China also to enjoy some company and savour the air conditioning on hot days. Some start as young as 13, trading from home with an eye on future careers in finance. Winning isn't guaranteed. This year, among the most turbulent in China's financial history, its stock markets more than doubled in the six months to May, only to crash amid concerns that growth in the country, which makes everything from cars to steel, is slowing faster than previously thought. (Photo by Aly Song/Reuters)

Caroline Wozniacki of Denmark serves to Alisa Kleybanova of Russia during the BNP Paribas Open at the Indian Wells Tennis Garden on March 15, 2011 in Indian Wells, California. (Photo by Matthew Stockman/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)