14 week-old twin polar bear cubs play during their first presentation to the media in Hellabrunn zoo on March 19, 2014 in Munich, Germany. The male and female twins were born on December 9, 2013 in the zoo. (Photo by Alexandra Beier/Getty Images)

A student from the General Yermolov Cadet School takes part in weapons training during a two-day field exercise near the village of Sengileyevskoye, just outside the south Russian city of Stavropol April 13, 2014. The General Yermolov Cadet School in the southern Russian city of Stavropol is a state-run institution that teaches military and patriotic classes in addition to a normal syllabus. (Photo by Eduard Korniyenko/Reuters)

A DC-10 air tanker delivers flame retardant to the Blue Cut fire in Wrightwood, Calif., Wednesday, August 17, 2016. A wildfire with a ferocity never seen before by veteran California firefighters raced up and down canyon hillsides, instantly engulfing homes and forcing thousands of people to flee, some running for their lives just ahead of the flames. (Photo by Alex Gallardo/AP Photo)

Matador Marco Espinola, who emigrated from the Azores two years ago, challenges a bull during an Azorean “tourada a corda” (bullfight by rope) in Brampton, Ontario August 15, 2015. Bulls in a tourada a corda are held by a rope controlled by a team of men to make sure the animal does not cause injury. Bulls are never killed, in contrast with bullfighting in Spain. The Portuguese population in Canada, numbering 429,000 in the 2011 census, mainly centers around Toronto with immigrants from the nine islands of the mid-Atlantic Azores archipelago. (Photo by Chris Helgren/Reuters)

Residents ride on top of an overcrowded “Jeepney”, a locally manufactured public transport, along a highway in Mogpog town on Marinduque island in central Philippines April 8, 2015. (Photo by Erik De Castro/Reuters)

A mahout rides an elephant at Tad Sae Waterfall outside Luang Prabang, Laos July 31, 2016. Protected by the United Nations cultural heritage agency UNESCO, Luang Prabang is one of the most alluring places in the region – a city that evokes old-world romance that has gained a reputation as a travellers' Shangri La. (Photo by Jorge Silva/Reuters)

Budgies feed on seeds from a local visitor's hands at Ocean Park in metro Manila, Philippines September 10, 2016. (Photo by Romeo Ranoco/Reuters)

People ride on a truck as they return to their families ahead of the Eid al-Adha festival in Khartoum September 11, 2016. (Photo by Mohamed Nureldin Abdallah/Reuters)