A woman jogs by the Tagus riverbank next to the April 25th bridge in Lisbon on a foggy morning, Monday, January 5, 2015. (Photo by Francisco Seco/AP Photo)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

Visitors stand atop a hill as fog rolls in from a view on Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

The sun sets behind powerplant smokestacks in Toronto, Friday, January 16, 2015. (Photo by Frank Gunn/AP Photo/The Canadian Press)

The sun sets behind a lamp in London January 8, 2015. (Photo by Stefan Wermuth/Reuters)

Demonstrators hold pencils in tribute to the victims of a shooting by gunmen at the offices of French satirical weekly Charlie Hebdo, during a demonstration organized by the NGO Rio de Paz (Rio of Peace) in Niteroi, near Rio de Janeiro, January 8, 2015. Armed and masked anti-terrorism police swooped on woodland villages northeast of Paris on Thursday in a manhunt for two brothers suspected of being the Islamist gunmen who killed 12 people at the French satirical weekly. (Photo by Ricardo Moraes/Reuters)

Boats are pictured during sunset at Herradura Beach in Punarenas, January 8, 2015. (Photo by Juan Carlos Ulate/Reuters)

A man looks at the Pudong financial district of Shanghai in this November 20, 2013, file photo. China's annual consumer inflation hovered at a near five-year low of 1.5 percent in December, little changed from November's levels, signalling persistent weakness in the economy but giving policymakers more room to ease policy to support growth. (Photo by Carlos Barria/Reuters)

People walk past an ash tree in front of the mountains of the lake Tegernsee during a sunny day in Warngau January 10, 2015. (Photo by Michael Dalder/Reuters)

A man pulls out a Ruffe from an ice hole as he fishes on the frozen Abakan Bay of the Yenisei River in Russia's Siberian city of Krasnoyarsk January 11, 2015. (Photo by Ilya Naymushin/Reuters)

A woman gets into the waters of Copacabana beach as the sun rises in Rio de Janeiro, January 12, 2015. (Photo by Ricardo Moraes/Reuters)

A waterbird swims in a canal bearing the reflection of trees in Beijing January 13, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A surfer heads home after riding the morning waves in Oceanside, California January 13, 2015. (Photo by Mike Blake/Reuters)

Crows fly across a field near the village of Dromore as heavy snow caused disruption across Northern Ireland January 16, 2015. (Photo by Cathal McNaughton/Reuters)

A woman is silhouetted against the Petronas Twin Towers as she has a souvenir photograph taken from the observatory deck of Kuala Lumpur Tower in Kuala Lumpur, Malaysia, Saturday, January 10, 2015. The Petronas Twin Towers is one of the major landmark in Kuala Lumpur city center alongside Kuala Lumpur Tower. (Photo by Joshua Paul/AP Photo)

Some trees are silhouetted in front of the rising sun over the horizon in Hajdusamson, 232 kilometers east of Budapest, on January 13, 2015 morning. (Photo by Zsolt Czegledi/EPA)

A backcountry skiier climbs up towards the Mederger Flue peak (2706 meters above sea level), on Monday, January 12, 2015, in Davos, Switzerland. (Photo by Gian Ehrenzeller/AP Photo/Keystone)

Kaisa Makarainen of Finland gestures to her coaches as she warms up prior to the women's 12.5 km mass start at the Biathlon World Cup in Ruhpolding, Germany, Sunday, January 18, 2015. (Photo by Matthias Schrader/AP Photo)

A man walks in front of a billboard featuring a globe at the Foreign Ministry in Berlin, Germany, Thursday, January 15, 2015. (Photo by Michael Sohn/AP Photo)

Runners in The Higos Insurance Services Somerton Handicap Hurdle Race make their way down the back straight at Wincanton racecourse on January 15, 2015 in Wincanton, England. (Photo by Alan Crowhurst/Getty Images)

Filipino firemen try to extinguish a fire at a residential area in Manila, Philippines, 12 January 2015. More than 100 houses were razed by a fire leaving around 300 families homeless in a residential area in Manila. The cause for the fire is yet to be determined, officials said. (Photo by Ritchie B. Tongo/EPA)

Indian people stands on the terrace of a building as they fly kites during a sunset in Ahmedabd, India, 06 January 2015. Kite-makers are preparing for the annual Hindu festival Makar-Sankranti (Uttarayan), during which people fly kites and compete in kite flying competitions. Makar-Sankranti is celebrated on 14 January of every year. (Photo by Divyakant Solanki/EPA)

Boys play with a ball at sunset in Yansi village, Donhe township in the Naga Self-Administered Zone in northwest Myanmar December 25, 2014. On Myanmar's mountainous frontier with India live the Naga, a group of tribes historically known as warriors who kept the heads of enemies they killed. In Myanmar, around 120,000 people live in the Naga Self-Administered Zone in Sagaing Division where they survive mainly by subsistence farming and hunting. Cultural practices are changing – for example, younger men now wear trousers rather than traditional loincloths – although many Naga communities remain impoverished and inaccessible by road. The Naga speak dozens of languages and many of those in Myanmar use Burmese as a lingua franca. (Photo by Soe Zeya Tun/Reuters)

A man walks near the April 25th bridge by the Tagus riverbank in Lisbon on a foggy morning, Monday, January 5, 2015. (Photo by Francisco Seco/AP Photo)

Ducks rest on the frozen surface of a lake illuminated by lights from a nearby bar in Beijing, Monday, January 12, 2015. Beijing's winter is a time to partake in winter activities such as ice skating, ice-karting and for the those hardy enough winter swimming. (Photo by Ng Han Guan/AP Photo)

Arctic sea smoke rises on the Royal River in Yarmouth, Maine, as a worker uses a push boat to break ice forming around a dredging operation, Wednesday morning, January 14, 2015. The temperature at sunrise was minus 8 degrees. Sea smoke occurs when extremely cold air passes over warmer water. (Photo by Robert F. Bukaty/AP Photo)