Fireworks explode over the St. Sava monument during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic 

Fireworks explode over the St. Sava monument during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic 

Fireworks explode over the St. Sava temple during the Orthodox Christian New Year's Day celebrations in Belgrade, Serbia, January 14, 2018. REUTERS/Djordje Kojadinovic 

Members of the Scintillating Fire Circus perform as approximately 70,000 people from all over the world gathered for the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 31, 2017. REUTERS/Jim Urquhart FOR USE WITH BURNING MAN RELATED REPORTING ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. NO THIRD PARTY SALES. NOT FOR USE BY REUTERS THIRD PARTY DISTRIBUTORS. 

Members of the Scintillating Fire Circus perform as approximately 70,000 people from all over the world gathered for the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 31, 2017. REUTERS/Jim Urquhart FOR USE WITH BURNING MAN RELATED REPORTING ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. NO THIRD PARTY SALES. NOT FOR USE BY REUTERS THIRD PARTY DISTRIBUTORS. 

Members of the Scintillating Fire Circus perform as approximately 70,000 people from all over the world gathered for the annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 31, 2017. REUTERS/Jim Urquhart FOR USE WITH BURNING MAN RELATED REPORTING ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. NO THIRD PARTY SALES. NOT FOR USE BY REUTERS THIRD PARTY DISTRIBUTORS. 

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows a coffee cup and roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows roasted coffee beans in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows bubbles in a coffee cup in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows coffee heating in an Italian coffee maker in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

An illustration picture shows a coffee cup near a laptop in Brussels, Belgium May 1, 2017. REUTERS/Eric Vidal/Illustration 

Guests show their excitement as they wait in viewing pens to see Pope Francis emerge from a private meeting with U.S. President Barack Obama upon the Pope's arrival at Joint Base Andrews outside Washington September 22, 2015.REUTERS/Jonathan Ernst 

Thrill-seekers ride a fairground attraction near the London Eye ferris wheel in London, Britain August 29, 2015. REUTERS/Neil Hall 

Thrill-seekers ride a fairground attraction near the London Eye ferris wheel in London, Britain August 29, 2015. REUTERS/Neil Hall TPX IMAGES OF THE DAY

Graduates toss their caps in the air at the conclusion of the commencement ceremony for the U.S. Naval Academy Class of 2015 in Annapolis, Maryland May 22, 2015. REUTERS/Kevin Lamarque TPX IMAGES OF THE DAY

Pope Francis arrives to attend a special audience with nuns of the Rome's diocese in Paul VI hall at the Vatican, May 16, 2015. REUTERS/Tony Gentile TPX IMAGES OF THE DAY

Afghan children enjoy a ride in Kabul March 30, 2015. REUTERS/Mohammad Ismail TPX IMAGES OF THE DAY

People visit a park with blooming flowers during spring in Shanghai March 24, 2015. REUTERS/Aly Song TPX IMAGES OF THE DAY

"Toquero" customers (L) react as they receive an electric shock together from the toquero's machine inside Tenampa restaurant at Garibaldi square in Mexico City March 22, 2015. Toqueros, using machines of their own manufacture, offer electric shocks of up to 120 volts for $1 to $2 dollars per person, which is popularly believed to help with stress and drunkenness, according to the Toqueros. REUTERS/Edgard Garrido 

Pope Francis is greeted by cloistered nuns at the Duomo during his pastoral visit in Naples March 21, 2015. REUTERS/Stefano Rellandini 

A Common Blue Morpho butterfly lands on the arm of Garbiella as it and hundreds of other butterflies from around the world fill the bird aviary for the next month at the San Diego Zoo Safari Park in San Diego, California March 13, 2015. Called the Butterfly Jungle, the exhibit has over 30 species of butterflies. REUTERS/Mike Blake (UNITED STATES - Tags: SOCIETY ANIMALS TRAVEL) 

Pakistan's Muhammad Irfan (L) celebrates dismissing South Africa's Dale Steyn (R) during their Cricket World Cup match in Auckland, March 7, 2015. REUTERS/Nigel Marple (NEW ZEALAND - Tags: SPORT CRICKET TPX IMAGES OF THE DAY) 

Singer Paloma Faith celebrates after receiving the British Female Solo Artist award at the BRIT music awards at the O2 Arena in Greenwich, London, February 25, 2015. REUTERS/Toby Melville (BRITAIN - Tags: ENTERTAINMENT TPX IMAGES OF THE DAY) 

Australia's Mitchell Marsh (R) celebrates dismissing England's captain Eoin Morgan (L) for a duck during their Cricket World Cup match at the Melbourne Cricket Ground (MCG) February 14, 2015. REUTERS/Hamish Blair (AUSTRALIA - Tags: SPORT CRICKET TPX IMAGES OF THE DAY) 

A riot policeman stands guard as Equatorial Guinea's fans cheer after their team beat Gabon in their Group A soccer match at the 2015 African Cup of Nations in Bata January 25, 2015. REUTERS/Mike Hutchings (EQUATORIAL GUINEA - Tags: SPORT SOCCER) 

Rafael Nadal of Spain celebrates after defeating Mikhail Youzhny of Russia in their men's singles first round match at the Australian Open 2015 tennis tournament in Melbourne January 19, 2015. REUTERS/Issei Kato (AUSTRALIA - Tags: SPORT TENNIS TPX IMAGES OF THE DAY)

Andy Murray of Britain reacts after gaining match point during his tennis match against Milos Raonic of Canada at the ATP World Tour finals at the O2 Arena in London November 11, 2014. REUTERS/Toby Melville (BRITAIN - Tags: SPORT TENNIS TPX IMAGES OF THE DAY) 

Ireland's John O'Shea, Stephen Ward and Marc Wilson (R-L) celebrate after their Euro 2016 Group D qualification soccer match against Germany in Gelsenkirchen, October 14, 2014. REUTERS/Wolfgang Rattay (GERMANY - Tags: SPORT SOCCER)

Alibaba Group Holding Ltd employees and executives use their mobile phones to take pictures as they arrive for the company's initial public offering (IPO) under the ticker "BABA" at the New York Stock Exchange in New York September 19, 2014. Alibaba Group Holding Ltd's shares surged in their first day of trading on Friday as investors jumped at the chance to get in on what looks likely to be the largest IPO in history and profit from China's growing middle class. REUTERS/Brendan McDermid (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY) 

Local resident Andreas Gibson celebrates with employees outside the Fifth Avenue Apple store after being the first to exit with an iPhone 6 in hand on the first day of sales in Manhattan, New York September 19, 2014. Apple Inc's latest phone lured throngs of gadget lovers, entrepreneurs and early adapters to its stores in New York, San Francisco and other cities around the world in the latest sign of strong initial demand for the new, larger generation of iPhones. REUTERS/Adrees Latif (UNITED STATES - Tags: BUSINESS SCIENCE TECHNOLOGY TELECOMS) 

Serena Williams of the U.S. celebrates a point against Ekaterina Makarova of Russia during their semi-final match at the 2014 U.S. Open tennis tournament in New York, September 5, 2014. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT TENNIS)

Members of the Field Marshall Montgomery Pipe Band react to winning the annual World Pipe Band Championships at Glasgow Green, Scotland August 16, 2014. The event includes 300 performances from about 223 pipe bands all around the world. REUTERS/Russell Cheyne (BRITAIN - Tags: SOCIETY TPX IMAGES OF THE DAY) 

Sri Lanka's captain Angelo Mathews celebrates after they win over the first test cricket match against Pakistan in Galle August 10, 2014. Sri Lanka beat Pakistan by seven wickets on the fifth day to win the first test and go 1-0 up in the two-test series on Sunday. REUTERS/Dinuka Liyanawatte (SRI LANKA - Tags: SPORT CRICKET TPX IMAGES OF THE DAY) 

High school students test their "Quipus" laptops during a presentation ceremony in El Alto, July 31, 2014. Some 15,000 public school students received the laptops, assembled by Bolivian state-run company Quipus, during the ceremony. According to local media, El Alto schools will receive a total of some 140,000 laptops this year as part of a government initiative to provide final-year high school students with access to a new laptop, aiming to incorporate the use of new technology in educational institutions. REUTERS/David Mercado (BOLIVIA - Tags: EDUCATION POLITICS SOCIETY) 

Catherine (R), Duchess of Cambridge, sits with her husband Prince William (C), and Britain's Prince Harry as they react watching hockey at the 2014 Commonwealth Games in Glasgow, Scotland, July 28, 2014. REUTERS/Russell Cheyne (BRITAIN - Tags: SPORT FIELD HOCKEY ROYALS)

People cheer after hearing the midday "Chupinazo" rocket announcing the start of the San Fermin festival in Pamplona July 6, 2014. Tens of thousands of expectant party goers holding red scarves squeeze into the town hall to kick off 204 hours of music, dancing, drinking, bullfighting and for the brave or unwary, an 825 metre (902 yard) daily sprint in front of six fighting bulls known as the Running Of The Bulls. REUTERS/Eloy Alonso (SPAIN - Tags: SOCIETY TPX IMAGES OF THE DAY) 

A girl has wine poured over her before the midday "Chupinazo" rocket announcing the start of the San Fermin festival in Pamplona July 6, 2014. Tens of thousands of expectant party goers holding red scarves squeeze into the town hall to kick off 204 hours of music, dancing, drinking, bullfighting and for the brave or unwary, an 825 metre (902 yard) daily sprint in front of six fighting bulls known as the Running Of The Bulls. REUTERS/Joseba Etxaburu (SPAIN - Tags: SOCIETY) 

Argentine soccer fans celebrate at the end of the
2014 World Cup quarter-finals between Argentina and Belgium at Copacabana beach in Rio de Janeiro, July 5, 2014. REUTERS/Pilar Olivares (BRAZIL - Tags: SOCCER SPORT WORLD CUP) 

Netherlands' fans cheer for their team at a fountain that contains orange-colored water, ahead of their 2014 World Cup quarter-final match against Costa Rica, in Salvador July 4, 2014. The Netherlands will play Costa Rica on July 5. REUTERS/Marcos Brindicci (BRAZIL - Tags: SOCCER SPORT WORLD CUP)

French President Francois Hollande (R) reacts as France team scores a goal against Nigeria in their 2014 World Cup round of 16 game at the Brasilia national stadium in Brasilia, at the Elysee Palace in Paris, June 30, 2014. REUTERS/Philippe Wojazer (FRANCE - Tags: POLITICS SPORT SOCCER WORLD CUP) 

Greek fans react as they watch a live broadcast of Greece's 2014 World Cup soccer match against Costa Rica, in Athens June 30, 2014. Greece's World Cup exit in the round of 16 on Sunday came as no real surprise after they again struggled for goals in a major international tournament, netting only three time in four games. REUTERS/Yorgos Karahalis (GREECE - Tags: SPORT SOCCER WORLD CUP TPX IMAGES OF THE DAY) 

Brazil soccer fans react as they watch the penalty shootout against Chile during a 2014 World Cup round of 16 game, at Guarulhos International Airport in Sao Paulo June 28, 2014. Brazil won the match. Picture taken June 28, 2014. REUTERS/Eddie Keogh (BRAZIL - Tags: SPORT SOCCER WORLD CUP) 

Brazil's national soccer players celebrate teammate Neymar's (R) decisive goal during a penalty shootout in their 2014 World Cup round of 16 game against Chile at the Mineirao stadium in Belo Horizonte June 28, 2014. Also pictured are (L-R) Brazil's Dani Alves, Jo,Marcelo, Hulk and Willian. REUTERS/Dylan Martinez (BRAZIL - Tags: SOCCER SPORT WORLD CUP TPX IMAGES OF THE DAY) TOPCUP 

Brazil fans celebrate after the team won their 2014 World Cup round of 16 game against Chile, at a fan fest in Porto Alegre June 28, 2014. REUTERS/Edgard Garrido (BRAZIL - Tags: SOCCER SPORT WORLD CUP)

Chile's Alexis Sanchez celebrates his goal against Brazil during their 2014 World Cup round of 16 game at the Mineirao stadium in Belo Horizonte June 28, 2014. REUTERS/Eric Gaillard (BRAZIL - Tags: SOCCER SPORT WORLD CUP TPX IMAGES OF THE DAY)

Petra Kvitova of Czech Republic reacts after defeating Venus Williams of the U.S. in their women's singles tennis match on Centre Court at the Wimbledon Tennis Championships in London June 27, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: SPORT TENNIS TPX IMAGES OF THE DAY)

Chile's Jorge Valdivia (C) celebrates his goal against Australia with his teammates during their 2014 World Cup Group B soccer match at the Pantanal arena in Cuiaba June 13, 2014. REUTERS/Eric Gaillard (BRAZIL - Tags: TPX IMAGES OF THE DAY SOCCER SPORT WORLD CUP)

Robin van Persie of the Netherlands (front) celebrates his goal against Spain with coach Louis van Gaal during their 2014 World Cup Group B soccer match at the Fonte Nova arena in Salvador June 13, 2014. REUTERS/Michael Dalder (BRAZIL - Tags: SOCCER SPORT WORLD CUP)

Andy Potts celebrates as he wins the 34th annual Escape from Alcatraz Triathlon in San Francisco, California June 1, 2014. Participants swim 1.5 miles (2.4 km) to shore, bike 18 miles (30 km) and finish with an 8-mile (13-km) run. REUTERS/Noah Berger (UNITED STATES - Tags: SPORT TRIATHLON TPX IMAGES OF THE DAY) 

Supporters of the Spanish national soccer team cheer before their friendly soccer match against Bolivia, in preparation for the 2014 World Cup in Brazil, outside the Ramon Sanchez Pizjuan stadium in Seville, May 30, 2014. REUTERS/Jon Nazca (SPAIN - Tags: SPORT SOCCER WORLD CUP) 

Chefs pose for a photograph as they take part in a Guinness World Record-breaking gathering of 3,634 chefs and sommeliers at the Angel of Independence monument in Mexico City, May 17, 2014. The Mexico City tourism board said a Guinness World Records official confirmed the event had set a new world record of the largest number of chefs and sommeliers to gather in one place. REUTERS/Henry Romero (MEXICO - Tags: SOCIETY) 

An Emirati skipper cheers for his crew mates in a rope-pulling competition against a French sailing team on the Sir Bu Nuayr Island, ahead of the Al Gaffal race, a long-distance sailing race of traditional wooden boats or dhows, near Sharjah May 16, 2014. Picture taken May 16, 2014.
REUTERS/Martin Dokoupil (UNITED ARAB EMIRATES - Tags: SPORT) 

Girls look at their hands after shaking hands with U.S. President Barack Obama (L) after he spoke at Bladensburg High School in Bladensburg, Maryland April 7, 2014. At right is a Secret Service agent. During his visit, Obama announced the winners of $107 million in grant money for high schools and partner organizations working to prepare students with skills needed for careers in industry after graduation.
REUTERS/Kevin Lamarque (UNITED STATES - Tags: POLITICS EDUCATION TPX IMAGES OF THE DAY) 

Russian fans react as they watch a broadcast of the ice hockey quarter-final match between Russia and Finland in the Olympic Park during the 2014 Winter Olympic Games in Sochi February 19, 2014. Russia were eliminated from the men's ice hockey competition at the Sochi Games on Wednesday following a 3-1 quarter-final loss to Finland. REUTERS/Shamil Zhumatov (RUSSIA - Tags: SPORT ICE HOCKEY OLYMPICS TPX IMAGES OF THE DAY) 

Winner Maiken Caspersen Falla (front) of Norway and her team mate, second placed Ingvild Flugstad Oestberg celebrate after competing in the women's cross-country sprint free final at the Sochi 2014 Winter Olympic Games in Rosa Khutor February 11, 2014. REUTERS/Carlos Barria (RUSSIA - Tags: OLYMPICS SPORT SKIING)