Gold bars from the vault of a bank and Swiss one franc coins are seen in this illustration picture taken in Zurich November 20, 2014. The “Save our Swiss gold” proposal, spearheaded by the right-wing Swiss People's Party (SVP), aims to ban the central bank from offloading its reserves and oblige it to hold at least 20 percent of its assets in gold. The referendum is scheduled for November 30. The SVP argues it would secure a stable Swiss franc. (Photo by Arnd Wiegmann/Reuters)

Saintsetseg Jambaldorj, a member of the Tsaatan ethnic minority, one of the last remaining groups of nomadic reindeer herders in East Taiga, Mongolia, wearing a traditional deel, on July 5, 2016. (Photo by Madoka Ikegami/Barcroft Images)

A man sits in the back of a taxi with a goat after purchasing it from a livestock market ahead of the Eid al-Adha festival in Kolkata, India, September 8, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

Russian Foreign Ministry spokeswoman Maria Zakharova dances during the reception in honour of heads of the delegations at the Russia-ASEAN summit in Sochi, Russia, May 19, 2016. (Photo by Host photo agency via Reuters)

Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

Gremio fans celebrate after their team won the Copa Libertadores final match at the Arena do Gremio in Porto Alegre, Brazil on November 29, 2017. (Photo by Diego Vara/Reuters)

A woman gets a pedicure in Port-au-Prince, Haiti, on October 13, 2017. (Photo by Andres Martinez Casares/AP Photo)