A Nigerian policeman inspects the site of a suicide attack by Boko Haram at a busy cattle market in the northeastern Nigerian city of Maiduguri in June, 2015. Boko Haram overtook ISIS as the world's deadliest terror group last year, according to the Global Terrorism Index, while Nigeria had the biggest year-on-year increase in terrorism, with deaths up more than 300%.
A Nigerian policeman inspects the site of a suicide attack by Boko Haram at a busy cattle market in the northeastern Nigerian city of Maiduguri in June, 2015. Boko Haram overtook ISIS as the world's deadliest terror group last year, according to the Global Terrorism Index, while Nigeria had the biggest year-on-year increase in terrorism, with deaths up more than 300%.
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In this image taken from social media, an ISIS fighter holds the group's flag as he stands on a tank, purportedly captured when they took over the town of Qaryatain, Syria. ISIS, along with Boko Haram, is one of two groups accounting for 51% of claimed terrorism deaths in 2014.
In this image taken from social media, an ISIS fighter holds the group's flag as he stands on a tank, purportedly captured when they took over the town of Qaryatain, Syria. ISIS, along with Boko Haram, is one of two groups accounting for 51% of claimed terrorism deaths in 2014.
From ISIS
A member of the Iraqi security forces fires ammunition in Baghdad in 2014 during a funeral procession of an Iraqi politician. The deadliest city in the world for terrorism is Baghdad. There were 2,454 deaths in Baghdad in 2014, with a death rate from terrorism of 43 per 100,000 people.
A member of the Iraqi security forces fires ammunition in Baghdad in 2014 during a funeral procession of an Iraqi politician. The deadliest city in the world for terrorism is Baghdad. There were 2,454 deaths in Baghdad in 2014, with a death rate from terrorism of 43 per 100,000 people.
HAIDAR MOHAMMED ALI/AFP/AFP/Getty Images
Iraqi counter-terrorism forces patrol a street in Tikrit in April 2015, a day after the country's prime minister declared victory in the battle to retake the city from ISIS.
Iraqi counter-terrorism forces patrol a street in Tikrit in April 2015, a day after the country's prime minister declared victory in the battle to retake the city from ISIS.
AHMAD AL-RUBAYE/AFP/AFP/Getty Images
An Iraqi Kurdish Peshmerga fighter prepares an ammunition belt as he guards a position at the frontline of fighting against ISIS militants near the northern Iraqi town of Sinjar.
An Iraqi Kurdish Peshmerga fighter prepares an ammunition belt as he guards a position at the frontline of fighting against ISIS militants near the northern Iraqi town of Sinjar.
SAFIN HAMED/AFP/AFP/Getty Images
A Syrian family waits after arriving on the Greek island of Lesbos along with other migrants and refugees, on November 17, 2015. Ten of the 11 countries most affected by terrorism also have the highest rates of refugees.
A Syrian family waits after arriving on the Greek island of Lesbos along with other migrants and refugees, on November 17, 2015. Ten of the 11 countries most affected by terrorism also have the highest rates of refugees.
BULENT KILIC/AFP/AFP/Getty Images