A military instructor helps a boy to shoot a rifle with blanks at a weapon exhibition during a military show in St.Petersburg, Russia, Sunday, January 17, 2016. (Photo by Dmitry Lovetsky/AP Photo)

A bride gets her make-up done before the start of a mass marriage ceremony in Kolkata, India, February 14, 2016. A total of 150 tribal Hindu, Muslim and Christian couples from various villages across the state took their wedding vows on Sunday during the day-long mass marriage ceremony organised by a social organisation, the organisers said. (Photo by Rupak De Chowdhuri/Reuters)

World's Greatest Swimming Pools: Four Seasons, Serengeti Pool, Tanzania. A show of elephants, buffalo and baboons awaits thanks to an active watering hole below the free-form infinity pool at this plush hideaway inside Serengeti National Park. Bonus: Because of infrared technology at the hole, guests can be notified on their bedroom TV when animals are approaching. When you've got word of wildlife on the horizon, catch them from your private terrace – or head back to the pool. (From $1,650). (Photo by Four Seasons)

A spectator cools herself at a water spraying fan at the Australian Open tennis championships in Melbourne, Australia, Tuesday, January 17, 2017. (Photo by Kin Cheung/AP Photo)

Emily Ratajkowski filming DKNY commercial on January 20, 2017 in New York City, USA. The 25-year-old model braved the freezing New York temperatures as she wore just a black lace bra and matching French knickers, with a pair of clumpy biker boots. (Photo by Startraks Photo/Rex Features/Shutterstock)

Afghan children wait as their mothers receive treatment at a USAID-funded health center on September 7, 2011 in Farza, Afghanistan. Almost 10 years after the 9/11 attacks and the U.S. invasion of Afghanistan, the U.S. government funds some of 500 Afghan health facilities nationwide, most run by non-governmental organizations contracted by the Afghan Ministry of Public Health. (Photo by John Moore/Getty Images)

Refugees and migrants try to find a place on an already full train headed for Serbia, near the city of Gevgelija, The Former Yugoslav Republic of Macedonia, on February 24, 2016. Refugees and migrants from Iraq and Syria continue to pass through Macedonia on their way to the European Union. (Photo by Georgi Licovski/EPA)

Prince Charles, Prince of Wales (R) and Camilla, Duchess of Cornwall (L) visit Seppeltsfield Winery in Barossa Valley, Australia, 10 November 2015. The royal couple are on a 12-day tour visiting seven regions in New Zealand and three states and one territory in Australia. (Photo by Daniel Kalisz/EPA)