An aerial view shows a Russian Troika, a sledge drawn by three horses, competing on the ice-covered Yenisei River during the annual Ice Derby amateur horse race near the Siberian settlement of Novosyolovo, south of Krasnoyarsk, Russia March 17, 2018. (Photo by Ilya Naymushin/Reuters)

A train attendant helps a passenger to adjust her seat at the business class carriage on a CRH 380A bullet train Thursday, June 16, 2011. (Photo by Reuters/China Daily)

A young boy plays with soap bubbles near Hofburg Palace at Heldenplatz, one of the top tourists attractions in Vienna, Austria, January 26, 2016. (Photo by Christian Bruna/EPA)

Reflected in an ornament, a reporter takes a photo of the White House Christmas Tree in the Blue Room during a media preview of the holiday decor at the White House in Washington, U.S., November 29, 2016. (Photo by Kevin Lamarque/Reuters)

Indian children help to push an auto rickshaw along a flooded street after heavy rain in Jalandhar on June 29, 2017, as the monsoon season begins. (Photo by Shammi Mehra/AFP Photo)

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)

A cyclist drives past a flowering rapeseed field not far from the small Bavarian village of Schoengeising, near Munich, during a nice, warm sunny weather day on May 17, 2017. (Photo by Christof Stache/AFP Photo)

Bo, a 55-day-old baby Echidna known as a puggle, rests in the hands of vet nurse Annabelle Sehlmeier at Taronga Zoo in Sydney November 1, 2012. The puggle was brought to the zoo after it being found by itself on a walking track north of Sydney and will be fed by hand until it is weaned at about six months of age. (Photo by Tim Wimborne/Reuters)