Members of Hashid Shaabi or Popular Mobilization Forces (PMF) fire towards Islamic State militant positions in west of Mosul, Iraq, December 28, 2016. (Photo by Reuters/Stringer)

A Somali police officer arrests a suspected rebel member of the al Qaeda-affiliated al Shabaab among beach goers in Mogadishu. Al Shabaab claimed responsibility for today's pre-dawn attack on a Kenyan university campus near the Somali border. The following gallery examines who is al Shabaab. Here: Somali police officer (R) arrests a suspected rebel member (L) of the Al Qaeda-affiliated al Shabaab among beach goers at the Lido beach north of Somalia's capital Mogadishu March 23, 2012. (Photo by Feisal Omar/Reuters)

In this photo taken late Thursday, May 7, 2015, a prison guard, left, and seated inmates cast shadows on a wall while waiting for the beginning of a rock concert by Romanian band Pro Musica, inside the Popa Sapca jail in Timisoara, western Romania. (Photo by Adi Piclisan/AP Photo)

A motor taxi driver gets his hands washed at an Ebola screening station on the road between Butembo and Goma on July 16, 2019 in Goma. The first patient to be diagnosed with Ebola in the eastern DR Congo city of Goma has died, the governor of North Kivu province said on July 16, 2019. The case – the first in a major urban hub in the region's nearly year-old epidemic of the disease – has sparked deep concern in neighbouring Rwanda and at the UN. (Photo by John Wessels/AFP Photo)

A woman prays as she touches the carcass of a male elephant after he, according to forest officials, was electrocuted early morning in a paddy field on the outskirts of Guwahati, India, June 20, 2017. (Photo by Anuwar Hazarika/Reuters)

A roadside vendor selling apples is seen through a plastic sheet that he uses to cover himself from rain, in Srinagar, Indian state of Jammu and Kashmir on November 14, 2018. (Photo by Danish Ismail/Reuters)

A female sniper of the Syrian Democratic Forces (SDF) monitors the area during a celebration at the iconic Al- Naim square in Raqa on October 19, 2017, after retaking the city from Islamic State (IS) group fighters. The SDF fighters flushed jihadist holdouts from Raqa' s main hospital and municipal stadium, wrapping up a more than four- month offensive against what used to be the inner sanctum of IS' s self- proclaimed “caliphate”. (Photo by Bulent Kilic/AFP Photo)

Furniture design “Chair” by Allen Jones ( £600,000-800,000) is seen at Christie's London on September 29, 2017 in London, England. Christie's Auction House is to sell millions of pounds worth of art and design from the 20th and 21st centuries during Frieze Week from October 3rd to October 7th. (Photo by Nils Jorgensen/Rex Features/Shutterstock)