The Villarrica Volcano is seen at night in Chile, April 16, 2016. Villarrica is one of Chile's most active volcanoes. Picture taken with long exposure. (Photo by Cristobal Saavedra/Reuters)

The Boeoegg, a giant symbolic snowman made of wadding and and filled with firecrackers burns on top of a bonfire in Sechselaeuten square on April 24, 2017 in Zurich. When the bells of the Saint Peter's church chime six o'clock, the bonfire under the snowman is set in fire and the guildsmen wearing historical costumes ride around the bonfire. The faster the head of the snowman explods the warmer and more beautiful the summer will be. (Photo by Michael Buholzer/AFP Photo)

A girl watches as Saen Dao, an eight-year-old female asian elephant, and her mahout perform underwater during a show at the Khao Kheow Open Zoo in Chonburi south of Bangkok on June 1, 2017. (Photo by Roberto Schmidt/AFP Photo)

This picture taken on October 20, 2016 shows students practising wushu at the Tagou martial arts school in Dengfeng. China is investing hugely in football training and has vowed to have 50 million school- age players by 2020, as the ruling Communist party eyes “football superpower” status by 2050. (Photo by Nicolas Asfouri/AFP Photo)

Germany's Wolfgang Kimmig-Liebe, who has been volunteering as Santa Claus for years, is searched by a Carabiniere paramilitary police officer before entering in St. Peter's Square at the Vatican to attend Pope Francis general audience, Wednesday, December 2, 2015. (Photo by Alessandra Tarantino/AP Photo)

UConn students from Storrs, Conn., Gary Tu, Danny Wang and Victor Zheng, fish at Shenipsit Lake in Tolland, Conn. during sunset on Tuesday, August 19, 2014. (Photo by Jim Michaud/AP Photo/Journal Inquirer)

A person stands in front of a 25.3-meter-long giant rabbit designed by Dutch artist Florentijn Hofman at an old aircraft hangar as part of the Taoyuan Land Art Festival in Taoyuan, northern Taiwan, September 3, 2014. The rabbit is named “Moon rabbit” for the coming Mid-Autumn Festival or the Moon Festival and will be displayed from September 4 to 14 at the Taoyuan military base. (Photo by Pichi Chuang/Reuters)

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)