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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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Alice Vitoria Gomes Bezerra, 3-months-old, who has microcephaly, is held by her mother Nadja Cristina Gomes Bezerra in Recife, Brazil. In the last four months, authorities have recorded close to 4,000 cases in Brazil in which the mosquito-borne Zika virus may have led to microcephaly in infants.
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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.