Republican U.S. presidential candidate Carson laughs at an answer from Trump at the 2016 U.S. Republican presidential candidates debate held by CNBC in Boulder

REUTERS/Rick Wilking

Republican U.S. presidential candidate Dr. Ben Carson (R) laughs at an answer from businessman Donald Trump (L) at the 2016 U.S. Republican presidential candidates debate held by CNBC in Boulder, Colorado.

Merkel in China

Soeren Stache/EPA

German Chancellor Angela Merkel reviews an honor guard as she is welcomed by China’s Prime Minister Li Keqiang (unseen) in Beijing, China, on Thursday

Palestinian protester tries to hammer a hole through the Israeli

Ammar Awad/Reuters

Palestinian protester tries to hammer a hole through the Israeli barrier that separates the West Bank town of Abu Dis from Jerusalem, as others wave Palestinian flags during clashes with Israeli troops.

Ferris wheel crew climb within the frame

Aung Thu/AFP/Getty Images

Ferris wheel crew climb within the framework of a human-powered ferris wheel to provide rotation for its passengers with their body weight during the Thadingyut full moon day festival in Yangon on Wednesday

Samuel Pepys: Plague, Fire, Revolution exhibition

Yui Mok/PA Wire

Workmen install the Portrait of Charles II in Coronation Robes by John Michael Wright at the National Maritime Museum , London, which is the largest object in their forthcoming exhibition Samuel Pepys: Plague, Fire, Revolution.

Army Photographic Competition 2015

Rupert Frere/MoD/Crown copyright/PA Wire

Former Garrison Sergeant Major, The Household Division and London District, WO1 William Mott OBE MVO inspecting Nijmegen Company Grenadier Guards. The photo by Sgt Rupert Frere, titled ‘How can you forget to shave?’, has been named Best Overall Professional Army PR Image in the Army Photographic Competition 2015.

Visitor falls down as they run away from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou

Reuters/China Daily

A visitor falls down as they run away from a wave caused by a tidal bore which surged past a barrier on the banks of Qiantang River, in Hangzhou, Zhejiang province, China, on Wednesday

A woman and her daughter walk past a line of riot police officers during a march to protest against the construction of the Interoceanic Grand Canal, in Managua City

Oswaldo Rivas/Reuters

A woman and her daughter walk past a line of riot police officers during a march to protest against the construction of the Interoceanic Grand Canal, in Managua City, Nicaragua.

Chinese President state visit - Day Four

MCFC/PA Wire

Sergio Aguero takes a selfie with Chinese President Xi Jinping and Prime Minister David Cameron as they visited the City Football Academy in Manchester on the last day of the state visit to the UK.

Bangladesh Hindu Festival

A.M. Ahad/AP

A Bangladeshi Hindu devotee dances in front of a Hindu temple on the last day of Durga Puja festival in Dhaka, Bangladesh, on Friday.

Young girl touches riot shield of police officer as she and other migrants walk after crossing border in Rigonce

Srdjan Zivulovic/Reuters

A young girl touches the riot shield of a police officer as she and other migrants make their way on foot after crossing the border from Croatia, in Rigonce, Slovenia, on Thursday.

U.S. President Obama hugs Vice President Biden after Biden announced he will not seek the 2016 Democratic presidential nomination during an appearance at the White House in Washington

Carlos Barria/Reuters

U.S. President Barack Obama hugs Vice President Joe Biden after Biden announced he will not seek the 2016 Democratic presidential nomination during an appearance in the Rose Garden of the White House in Washington.

A woman walks past posters for ruling party Chama Cha Mapinduzi (CCM) presidential candidate John Magufuli and parliamentary candidate Hassan Zungu on October 20, 2015 in Dar es Salaam. AFP PHOTO / Daniel HaydukDaniel Hayduk/AFP/Getty Images

Daniel Hayduk/AFP/Getty Images

A woman walks past posters for ruling party Chama Cha Mapinduzi (CCM) presidential candidate John Magufuli and parliamentary candidate Hassan Zungu, in Dar es Salaam.

Iraqi Shiite fighters

Ahmad Al Rubaye/AFP/Getty Images

Iraqi Shia fighters from the Popular Mobilisation units, fighting alongside Iraqi government forces, fire a rocket during a military operation against Islamic State (IS) group jihadists as they advance towards the centre of Baiji, some 200 kilometres north of Baghdad.

Migrants jump over a fence as they attempt to cross the Croatian border near the village of Berkasovo

Marko Djurica/Reuters

Migrants jump over a fence as they attempt to cross the Croatian border near the village of Berkasovo, Serbia on Monday. Thousands of migrants clamoured to enter European Union member Croatia from Serbia on Monday after a night spent in the cold and mud of no-man’s land, their passage west slowed by a Slovenian effort to impose limits on the flow to western Europe.

A man sleeps on two chairs beside a road in Beijing

Jason Lee/Reuters

A man sleeps on two chairs beside a road in Beijing, China, on Friday

London's Mayor Boris Johnson collides with Toki Sekiguchi during a game of Street Rugby with  in Tokyo

Issei Kato/Reuters

London’s Mayor Boris Johnson collides with 10-year-old Toki Sekiguchi during a game of Street Rugby with a group of Tokyo children, outside the Tokyo Square Gardens building on Thursday.

Democratic U.S. presidential candidate Hillary Clinton arrives with Nevada State Assemblyman Nelson Araujo to purchase ice cream between campaign events in North Las Vegas

David Becker/Reuters

Democratic U.S. presidential candidate Hillary Clinton (L) arrives with Nevada State Assemblyman Nelson Araujo to purchase ice cream between campaign events in North Las Vegas, Nevada.

A Mapuche Indian activist prepares to throw a stone at riot police vehicle during a protest march against Columbus Day in downtown Santiago

Ivan Alvarado/Reuters

A Mapuche Indian activist prepares to throw a stone at a riot police vehicle during a protest march by Mapuche Indian activists against Columbus Day in downtown Santiago, Chile.