A three-month-old Sumatran tiger cub named “Bandar” shows his displeasure after being dunked in the tiger exhibit moat for a swim reliability test at the National Zoo in Washington, on November 6, 2013. All cubs born at the zoo must take a swim test before being allowed to roam in the exhibit. Bandar passed his test. (Photo by Manuel Balce Ceneta/Associated Press)

Then U.S. Army First Lieutenant Kirsten Griest (C) and fellow soldiers participate in combatives training during the Ranger Course on Fort Benning, Georgia, in this handout photograph taken on April 20, 2015 and obtained on August 20, 2015. When Griest and another woman completed the daunting U.S. Army Ranger school this week they helped end questions about whether women can serve as combat leaders, as the Pentagon is poised to open new roles, including elite Navy SEALs, to women in coming months. The feat by Griest and First Lieutenant Shaye Haver followed a re-evaluation of the role of women after their frontline involvement in Iraq and Afghanistan and the end of a rule barring them from combat roles in 2013. (Photo by Spc. Nikayla Shodeen/Reuters/U.S. Army)

Female labourers wearing helmets take a break from laying underground electricity cables in Ahmedabad, India, March 7, 2016. (Photo by Amit Dave/Reuters)

A participant dressed as a mermaid goes to swim in the beach after taking part in the Annual Mermaid Parade in Brooklyn, New York, June 18, 2016. The annual parade, founded in 1983, seeks to bring mythology to life for residents, create confidence in the district and to allow artistic self-expression in public, according to the parade's website. (Photo by Eduardo Munoz/Reuters)

A man takes a shower on a street from water coming from a drainpipe as it rains in Havana, Cuba, Wednesday, July 27, 2016. During the last couple of weeks short but intense tropical downpours have been coming down of Havana every afternoon. (Photo by Desmond Boylan/AP Photo)

Tsewang Dolma, 33, a farmer and housewife poses for a photograph in Matho, a village nestled high in the Indian Himalayas, India September 29, 2016. When asked how living in the world's fastest growing major economy had affected life, Dolma replied: “Our culture is spoiled now. We don't wear our traditional dress”. (Photo by Cathal McNaughton/Reuters)

A woman weeps after an announcement that Thailand's King Bhumibol Adulyadej has died, at the Siriraj hospital in Bangkok, Thailand, October 13, 2016. Thailand's Royal Palace says King Bhumibol, the world's longest-reigning monarch, has died at age 88. (Photo by Athit Perawongmetha/Reuters)

Workers lay railway track in a tunnel of the Crossrail project in Stepney, east London, Britain, November 16, 2016. Crossrail, which is Europe's largest construction project, is a railway link which will connect outlying areas to the east and west of London with tunnels under the centre of the capital. (Photo by Stefan Wermuth/Reuters)