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Campaign volunteers listen as Democratic presidential candidate Sen. Bernie Sanders speaks during a campaign event at Five Sullivan Brothers Convention in Waterloo, Iowa.
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A competitor emerges from the water during the Tough Guy Challenge at South Perton Farm in Telford, England.
ANGELOS TZORTZINIS / AFP - Getty Images
A migrant boy holds blankets as he disembarked from the passenger ferry Blue Star arriving from the Greek island of Lesbos at the port of Piraeus in Athens.
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Israeli soldiers react as they secure the scene of a reported Palestinian shooting attack at a checkpoint near the Beit El settlement, close to West Bank city of Ramallah. A Palestinian opened fire at a checkpoint near the Jewish settlement in the West Bank, wounding three Israelis before being shot dead.
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Republican presidential candidate Jeb Bush speaks at a campaign event at his local field office in Hiawatha, Iowa. The Democratic and Republican Iowa Caucuses, the first step in nominating a presidential candidate from each party, will take place on February 1.
SCOTT MORGAN / Reuters
U.S. Republican presidential candidate Donald Trump is mobbed by supporters after a campaign rally in Council Bluffs, Iowa.
BRIAN SNYDER / Reuters
U.S. Democratic presidential candidate Hillary Clinton is greeted by a young girl as she arrives to speak at a campaign rally at Abraham Lincoln High School in Council Bluffs.
LOUAI BESHARA / AFP - Getty Images
Syrian security forces and residents gather at the site of suicide bombings in the area of a revered Shiite shrine in the town of Sayyida Zeinab, on the outskirts of the capital Damascus.
ILYA NAYMUSHIN / Reuters
A car tows a snowboarder along the frozen surface of the Yenisei River in Taiga district, with the air temperature at about minus 13 degrees, outside Krasnoyarsk, Siberia, Russia.