Ivan Timofeenko, co-founder of "Newton Park", a private interactive museum of science, dressed as Santa Claus, pours liquid nitrogen, bearing the temperature of about minus 196 degrees Celsius (minus 320.8 degrees Fahrenheit), on the head of visitor Dmitry Shilov during the "Arctic" scientific show for school children at the "Square of Peace" museum centre in the Siberian city of Krasnoyarsk, Russia, December 24, 2015. A group of young engineers, scientists and researchers, who specialize in chemistry, applied mathematics and physics, founded the interactive museum of science to conduct experiments aimed at the popularization of the exact sciences for pupils and their parents. The experiment demonstrated the Leidenfrost effect phenomenon, in which a liquid produces a layer of insulating vapour that prevents the liquid getting into a direct contact with a surface much hotter than the liquid's boiling point, according to organizers. REUTERS/Ilya Naymushin 

Gold medallists in the ice dance competition Maia and Alex Shibutani of the U.S. pose with silver medallists Ekaterina Bobrova (L) and Dmitri Soloviev (2nd L) of Russia and bronze medallists Madison Hubbell (2nd R) and Zachary Donohue (R) of the U.S. during the presentation ceremony at the ISU Grand Prix of Figure Skating in Nagano, Japan, November 29, 2015. REUTERS/Yuya Shino

Kaitlyn Weaver and Andrew Poje of Canada (C) celebrate with their gold medals after winning the Ice Dance competition along with second placed Maia Shibutani and Alex Shibutani of the U.S. (L) and third placed Ekaterina Bobrova and Dmitri Soloviev of Russia (R) at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance free dance program at Skate Canada International in Lethbridge, Alberta October 31, 2015. REUTERS/Jim Young

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance short dance program at Skate Canada International in Lethbridge, Alberta October 30, 2015. Fifty-six Olympic and world championship athletes are competing in the event, which is the second of six stops on the International Skating Union (ISU) Grand Prix of Figure Skating Series. REUTERS/Jim Young 

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance short dance program at Skate Canada International in Lethbridge, Alberta October 30, 2015. Fifty-six Olympic and world championship athletes are competing in the event, which is the second of six stops on the International Skating Union (ISU) Grand Prix of Figure Skating Series. REUTERS/Jim Young 

Ekaterina Bobrova and Dmitri Soloviev of Russia perform during the Ice Dance short dance program at Skate Canada International in Lethbridge, Alberta October 30, 2015. Fifty-six Olympic and world championship athletes are competing in the event, which is the second of six stops on the International Skating Union (ISU) Grand Prix of Figure Skating Series. REUTERS/Jim Young 

Anatoly Litvinenko, the son of murdered KGB agent Alexander Litvinenko, leaves the High Court in central London, July 28, 2015. The head of a British inquiry into the death of Alexander Litvinenko, poisoned with a radioactive isotope in London in 2006, accused Russian authorities and a Russian man suspected of murdering the ex-KGB spy of trying to undermine his probe. British authorities say there is evidence to prove Dmitry Kovtun, along with fellow Russian Andrei Lugovoy, poisoned Kremlin critic Litvinenko with green tea laced with polonium-210 at the Millennium Hotel in central London. REUTERS/Paul Hackett

Soldiers react as they walk past coffins of troops killed after the collapse of a section of a barracks during a funeral ceremony in Omsk, Russia, July 14, 2015. At least 23 soldiers were killed when a military barracks collapsed in Russia's Omsk region, Russian news agencies said on Monday. REUTERS/Dmitry Feoktistov TPX IMAGES OF THE DAY

Russia's Victor Faizulin (L) and Dmitry Kombarov fight for the ball with South Korea's Park Chu-young, as Russia's Denis Glushakov watches, during their 2014 World Cup Group H soccer match at the Pantanal arena in Cuiaba June 17, 2014. REUTERS/David Gray (BRAZIL - Tags: TPX IMAGES OF THE DAY SOCCER SPORT WORLD CUP)

Russia's Victor Faizulin (L) and Dmitry Kombarov fight for the ball with South Korea's Park Chu-young during their 2014 World Cup Group H soccer match at the Pantanal arena in Cuiaba June 17, 2014. REUTERS/David Gray (BRAZIL - Tags: TPX IMAGES OF THE DAY SOCCER SPORT WORLD CUP)

South Korea's Park Chu-young fights for the ball with Russia's Dmitry Kombarov during their 2014 World Cup Group H soccer match at the Pantanal arena in Cuiaba June 17, 2014. REUTERS/David Gray (BRAZIL - Tags: SOCCER SPORT WORLD CUP)

The Russian figure skating team steps onto the podium at the Sochi 2014 Winter Olympics, February 9, 2014. From left to right: Ekaterina Bobrova and Dmitri Soloviev, Tatiana Volosozhar and Maxim Trankov, Ksenia Stolbova and Fyodor Klimov, Yulia Lipnitskaya, Elena Ilinykh and Nikita Katsalapov, Evgeny Plyushchenko. REUTERS/Brian Snyder (RUSSIA - Tags: SPORT FIGURE SKATING OLYMPICS TPX IMAGES OF THE DAY) 

The president and CEO of the Sochi Olympic Organizing Committee Dmitry Chernyshenko speaks during the opening ceremony of the 2014 Sochi Winter Olympics, February 7, 2014. REUTERS/Jim Young (RUSSIA - Tags: OLYMPICS SPORT)

Ekaterina Bobrova (top) and Dmitri Soloviev of Russia
perform during the ice dance short dance programme at the ISU Grand Prix of Figure Skating Rostelecom Cup in Moscow, November 22, 2013. REUTERS/Grigory Dukor (RUSSIA - Tags: SPORT FIGURE SKATING) 

Sergei Filin (2nd R), artistic director of Russia's Bolshoi Ballet, Dmitry Vdovin (R), artistic director of the Bolshoi Theatre Young Artists Opera Programme, Vladimir Urin (4th R), director general of the Bolshoi Theater, Alexander Zhukov (3rd R), chairman of the Bolshoi Theatre Board of Trustees, and culture minister Vladimir Medinsky (3rd L) attend a meeting with dancers at the Bolshoi Theatre in Moscow, September 17, 2013. The artistic director of Russia's Bolshoi Ballet is returning to Moscow from Germany following eight months and 22 operations on his eyes and face after an acid attack that nearly blinded him, the theatre's spokeswoman said. REUTERS/Maxim Shemetov (RUSSIA - Tags: ENTERTAINMENT CRIME LAW) 

A student smokes on a street in Moscow October 16, 2012. Russian Prime Minister Dmitry Medvedev launched a crackdown on smoking on Tuesday with a bill to ban tobacco advertising and raise taxes on cigarettes in the world's second largest tobacco market after China. REUTERS/Maxim Shemetov (RUSSIA - Tags: POLITICS SOCIETY HEALTH EDUCATION) 

People pass by a portrait of Russian Prime Minister Dmitry Medvedev at a camp, The Territory of the Initiative Youth "Biryusa", on the bank of the Yenisei river in the Siberian Taiga, some 60 km (37 miles) south of Russian city of Krasnoyarsk, July 28, 2012. The Territory of Initiative Youth was first held in the Biryusa Bay, on the shores of the Krasnoyarsk Sea in 2007, bringing together young people with different talents and skills. The project serves as an annual meeting place for over 5,000 representatives of various youth movements, NGOs and professional communities from Siberian Federal District in general, according to organizers. Picture taken July 28. REUTERS/Ilya Naymushin (RUSSIA - Tags: SOCIETY) 

A supporter of jailed opposition leader Yulia Tymoshenko sits outside the prison, where Tymoshenko is being held, in Kharkiv May 4, 2012. International pressure mounted on Ukraine on Thursday over its treatment of jailed opposition leader Yulia Tymoshenko, but Kiev warned that any boycott of the European soccer championship next month would only hurt the interests of football fans. REUTERS/Dmitry Neymyrok (UKRAINE - Tags: CRIME LAW POLITICS) 

Russia's President Dmitry Medvedev (L) walks beside his South Korean counterpart Lee Myung-bak before their meeting at the presidential house in Seoul March 26, 2012. South Korea hosts some 50 world leaders at a two-day nuclear security summit starting on Monday. REUTERS/Ahn Young-joon/Pool (SOUTH KOREA - Tags: POLITICS) 

Russia's President Dmitry Medvedev (L) is greeted by his South Korean counterpart Lee Myung-bak before their meeting at the presidential house in Seoul March 26, 2012. South Korea hosts some 50 world leaders at a two-day nuclear security summit starting on Monday. REUTERS/Ahn Young-joon/Pool (SOUTH KOREA - Tags: POLITICS) 

Russia's President Dmitry Medvedev (L) shakes hands with his South Korean counterpart Lee Myung-bak before their meeting at the presidential house in Seoul March 26, 2012. South Korea hosts some 50 world leaders at a two-day nuclear security summit starting on Monday. REUTERS/Ahn Young-joon/Pool (SOUTH KOREA - Tags: POLITICS) 

Russian President Dmitry Medvedev (R) waves as Moscow's Mayor Sergei Sobyanin (L) looks on during an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (2nd R) has a drink with award winners and Presidential Administration chief of staff Sergei Ivanov (R) during an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS SCIENCE TECHNOLOGY) 

Russian President Dmitry Medvedev (L) bows during an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev smiles during an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev smiles during an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev (C) speaks during an address at an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

Russian President Dmitry Medvedev gestures during an address at an awards ceremony in Moscow's Kremlin February 8, 2012. Medvedev presented awards to young scientists for achievements in science and innovation. REUTERS/Sergei Karpukhin (RUSSIA - Tags: POLITICS) 

U.S. President Barack Obama addresses the first plenary meeting of the APEC Summit in Honolulu, Hawaii November 13, 2011. Also in the picture is Russian President Dmitry Medvedev. REUTERS/Jim Young (UNITED STATES - Tags: POLITICS BUSINESS) 

Canadian Prime Minister Stephen Harper (R) greets Russia's President Dmitry Medvedev (L) as U.S. President Barack Obama looks on during the first plenary meeting at the APEC Summit in Honolulu, Hawaii November 13, 2011. REUTERS/Jim Young (UNITED STATES - Tags: POLITICS) 

Members of an internet support community called Medvedev's Girls attend a meeting of Russian President Dmitry Medvedev with bloggers in Moscow's Kremlin November 9, 2011. REUTERS/Alexander Nemenov/Pool (RUSSIA - Tags: POLITICS SOCIETY) 

A member of a local social network group calling themselves "Medvedev girls" displays a gift for Russian President Dmitry Medvedev's birthday to authorities in the Kremlin September 14, 2011. President Medvedev celebrated his 46th birthday on Wednesday. REUTERS/Denis Sinyakov (RUSSIA - Tags: POLITICS SOCIETY) 

A young woman kisses a board displaying Russia's President Dmitry Medvedev on International Kissing Day, in front of the Kremlin, in central Moscow July 6, 2011. Members of the "Medvedev is our president" internet community organized the "Kiss Medvedev" event to mark International Kissing Day, according to the organizers. REUTERS/Sergei Karpukhin (RUSSIA - Tags: SOCIETY POLITICS) 

Young women kiss a board displaying Russia's President Dmitry Medvedev on International Kissing Day, in front of the Kremlin, in central Moscow July 6, 2011. Members of the "Medvedev is our president" internet community organized the "Kiss Medvedev" event to mark International Kissing Day, according to the organizers. The board records the number of kisses carried out. REUTERS/Sergei Karpukhin (RUSSIA - Tags: SOCIETY POLITICS IMAGES OF THE DAY) 

Russia's President Dmitry Medvedev (back) delivers a speech during a ceremony to award Russian young cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev (R) decorates pianist Ekaterina Mechetina with a badge during a ceremony to award Russian young cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev (R) pins a badge onto poet Maria Markova, during a ceremony to award young Russian cultural workers, in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS SOCIETY) 

Russia's President Dmitry Medvedev (R) shakes hands with Darima Bazarova, the head of the centre of national and local history documents under the Buryat National Library, during a ceremony to award young Russian cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS SOCIETY) 

Russia's President Dmitry Medvedev raises his glass in a toast during a ceremony to award young Russian cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev applauds during a ceremony to award young Russian cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev adjusts microphones as he delivers a speech during a ceremony to award young Russian cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev delivers a speech during a ceremony to award Russian young cultural workers in Moscow's Kremlin June 28, 2011. REUTERS/Alexander Natruskin (RUSSIA - Tags: POLITICS) 

Russia's President Dmitry Medvedev looks on at a joint news conference during the BRICS (Brazil, Russia, India, China and South Africa) Summit in Sanya, Hainan Province April 14, 2011. REUTERS/How Hwee Young/Pool (CHINA - Tags: POLITICS) 

Russia's President Dmitry Medvedev (C) gestures as he talks to India's Prime Minister Manmohan Singh (L), next to China's President Hu Jintao, during a joint news conference at the BRICS Leaders Meeting in Sanya, Hainan province April 14, 2011. The development banks of the five BRICS nations agreed in principle on Thursday to establish mutual credit lines denominated in their local currencies, not in dollars. REUTERS/How Hwee Young/Pool (REUTERS - Tags: POLITICS BUSINESS) 

Russia's President Dmitry Medvedev gestures as he speaks during a joint news conference at the BRICS Leaders Meeting in Sanya, Hainan province April 14, 2011. The development banks of the five BRICS nations agreed in principle on Thursday to establish mutual credit lines denominated in their local currencies, not in dollars. REUTERS/How Hwee Young/Pool (REUTERS - Tags: POLITICS BUSINESS) 

Russia's President Dmitry Medvedev (L) looks at China's President Hu Jintao during a joint news conference at the BRICS Leaders Meeting in Sanya, Hainan province April 14, 2011. The development banks of the five BRICS nations agreed in principle on Thursday to establish mutual credit lines denominated in their local currencies, not in dollars. REUTERS/How Hwee Young/Pool (REUTERS - Tags: POLITICS BUSINESS) 

China's President Hu Jintao (2nd R) gestures to Brazil's President Dilma Rousseff (R), next to India's Prime Minister Manmohan Singh (L) and Russia's President Dmitry Medvedev, as they take their seats at a joint news conference at the BRICS Leaders Meeting in Sanya, Hainan province April 14, 2011. The development banks of the five BRICS nations agreed in principle on Thursday to establish mutual credit lines denominated in their local currencies, not in dollars. REUTERS/How Hwee Young/Pool (REUTERS - Tags: POLITICS BUSINESS) 

(L-R) India's Prime Minister Manmohan Singh, Russia's President Dmitry Medvedev, China's President Hu Jintao, Brazil's President Dilma Rousseff and South African President Jacob Zuma attend a joint news conference at the BRICS Leaders Meeting in Sanya, Hainan province April 14, 2011. The development banks of the five BRICS nations agreed in principle on Thursday to establish mutual credit lines denominated in their local currencies, not in dollars. REUTERS/How Hwee Young/Pool (REUTERS - Tags: POLITICS BUSINESS) 

Russia's President Dmitry Medvedev (R) meets with young ice hockey players, with prominent Soviet ice hockey player Alexander Yakushev standing nearby, at the 'Yantar' (Amber) sports complex on the outskirts of Moscow March 31, 2011. REUTERS/Dmitry Kostyukov/Pool (RUSSIA - Tags: SPORT ICE HOCKEY POLITICS) 

Photos of the Young Front opposition group leaders Dmitry Dashkevich and opposition activist Eduard Lobov looking through bars during a court hearing lie with flowers in central Minsk March 25, 2011. Protesters gathered in the capital to mark the anniversary of the foundation of the Independent Republic in 1918. REUTERS/Vasily Fedosenko(BELARUS - Tags: ANNIVERSARY CIVIL UNREST POLITICS) 

Leader of the Young Front opposition group Dmitry Dashkevich (front) and opposition activist Eduard Lobov look through the bars during a court hearing in Minsk March 24, 2011. The activists are on trial for hooliganism and assault and battery of two men on the eve of the presidential election in Belarus on December 19, 2010, according to local media. REUTERS/Julia Darashkevich (BELARUS - Tags: CRIME LAW POLITICS ELECTIONS) 

Leader of the Young Front opposition group Dmitry Dashkevich (L) and opposition activist Eduard Lobov look through the bars during a court hearing in Minsk March 24, 2011. The activists are on trial for hooliganism and assault and battery of two men on the eve of the presidential election in Belarus on December 19, 2010, according to local media. REUTERS/Julia Darashkevich (BELARUS - Tags: CRIME LAW POLITICS ELECTIONS) 

An activist of the pro-Kremlin Molodaya Gvardiya (Young Guard) movement protests against Japan over a disputed island chain in front of the Japanese embassy in Moscow February 8, 2011. A row between Russia and Japan over the disputed island chain, which Russia calls the Southern Kurile islands and which Japan calls its Northern Territories, escalated on Monday, with Japan criticising a visit to the islands by Russian President Dmitry Medvedev while Russia claimed Japan funds anti-Russian groups. REUTERS/Nikolay Korchekov (RUSSIA - Tags: POLITICS CIVIL UNREST) 

Activists of the pro-Kremlin Molodaya Gvardiya (Young Guard) movement protest against Japan over a disputed island chain in front of the Japanese embassy in Moscow February 8, 2011. A row between Russia and Japan over the disputed island chain, which Russia calls the Southern Kurile islands and which Japan calls its Northern Territories, escalated on Monday, with Japan criticising a visit to the islands by Russian President Dmitry Medvedev while Russia claimed Japan funds anti-Russian groups. REUTERS/Nikolay Korchekov (RUSSIA - Tags: POLITICS CIVIL UNREST) 

Activists of the pro-Kremlin Molodaya Gvardiya (Young Guard) movement protest against Japan over a disputed island chain in front of the Japanese embassy in Moscow February 8, 2011. A row between Russia and Japan over the disputed island chain, which Russia calls the Southern Kurile islands and which Japan calls its Northern Territories, escalated on Monday, with Japan criticising a visit to the islands by Russian President Dmitry Medvedev while Russia claimed Japan funds anti-Russian groups. REUTERS/Nikolay Korchekov (RUSSIA - Tags: POLITICS CIVIL UNREST)