Participants costumed as zombies try to catch hobby runners during the so-called Zombie-Run at the harness racing track Karlshorst in Berlin, Germany, 18 May 2014. The runners carry small flags in their belts which they have to get safely across the finishing line while the zombies try to steal them. The sporting event is based on the US television series “The Walking Dead”. (Photo by Soeren Stache/DPA)

Londoners walking through Potters Field Park were surprised to see a “money tree” blooming with £9820 in £10 notes, the average amount a working British family has in savings, on July 24, 2014 in London, England. The tree was planted by Sunlife to encourage the nation to start saving at least £10 a month for a brighter future. (Photo by Tristan Fewings/Getty Images for SunLife)

A Sri Lankan activist, who wrapped himself with fire crackers, walks in Colombo on July 23, 2014 to symbolically demonstrate against people burned during Anti-Tamil riots on the island thirty-one years ago. Official accounts placed the death toll at 400 while human rights activists put the toll at thousands. (Photo by Ishara S.Kodikara/AFP Photo)

A combination picture shows Will Adam, 14, snowboarding down a street on Beacon Hill during a large winter blizzard in Boston, Massachusetts, United States January 27, 2015 (top), and a woman looking at her phone as she walks down the same street June 13, 2015. Outdoor scenes in Boston show local residents enjoying balmy weather amid lush greenery as the summer solstice approaches on 21 June. The very same locations suffered heavy snowstorms last winter, with snow ploughs, skiers and snowboarders battling the drifts. Boston got 275.8 cm of snow over the winter, the most since 1872, when records began. A few months after the snowstorms, Brian Snyder revisited the same places and shot pictures at exactly the same locations. (Photo by Brian Snyder/Reuters)

Irina, worker of a petrol station, now member of reconnaissance team of pro-Russian rebels' in the town of Makievka, eastern Ukraine, October 6, 2014. Like the men in the conflict, the women come from all walks of life. Some women come to serve with their husbands and boyfriends, others are single. Female fighters on both sides said the men in their units treat them as equals, though sometimes showing more leniency. They have little respect for men who have not taken up arms. On both sides the fighters expect a long conflict, despite the fragile ceasefire now in place. (Photo by Shamil Zhumatov/Reuters)

A giant shoe is pictured outside a life-size “Barbie Dreamhouse” of Mattel's Barbie dolls in Berlin, May 15, 2013. The life-sized house, covering about 1,400 square metres offers visitors to try on Barbie's clothes in her walk-in closet, tour her living room and her kitchen. (Photo by Fabrizio Bensch/Reuters)

Afghan air force 2nd Lt. Niloofar Rhmani walks the flight line at Shindand Air Base, Afghanistan, prior to her graduation from undergraduate pilot training, on May 13, 2013. Rhmani made history on May 14, when she became the first female to successfully complete undergraduate pilot training and earn the status of pilot in more than 30 years. She will continue her service as she joins the Kabul Air Wing as a Cessna 208 pilot. (Photo by Senior Airman Scott Saldukas/USAF)

A police officer wearing a protective mask walks past the portrait of late communist leader Mao Zedong (not pictured) at Tiananmen Gate in Beijing on January 23, 2020. Large-scale Lunar New Year events in Beijing have been cancelled as part of national efforts to control the spread of a new SARS-like virus, city authorities announced on January 23. (Photo by Nicolas Asfouri/AFP Photo)