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)

A man is silhouetted in front of the Allianz-Arena as he walks his dogs at sunrise in Munich, southern Germany, Friday, April 10, 2015. (Photo by Peter Kneffel/AP Photo/DPA)

A boy looks on as fire fighters try to extinguish the fire at oil wells, were set on fire by Daesh terrorists as they fled after Al Qayyarah town's cleansing from Daesh militants as the operation to retake Iraq's Mosul from Daesh continues, in Al Qayyarah Town of Mosul, Nineveh, Iraq on November 02, 2016. (Photo by Yunus Keles/Anadolu Agency/Getty Images)

People walk along Beachy Head, close to Eastbourne on the south coast of England on April 12, 2020, as life in Britain continues over the Easter break, during the nationwide lockdown to combat the novel coronavirus pandemic. Britain's Prime Minister Boris Johnson was making “very good progress” on Saturday in his recovery in hospital from coronavirus, officials said, as the country's deaths toll from the disease approached the grim milestone of 10,000. (Photo by Ben Stansall/AFP Photo)

Buddhist believers wearing faces masks to help protect against the spread of the new coronavirus wait to attend a service to pray for overcoming the COVID-19 outbreak and to celebrate Buddha's birthday at the Chogyesa temple in Seoul, South Korea, Thursday, April 30, 2020. (Photo by Ahn Young-joon/AP Photo)

This picture taken on June 20, 2020 shows longtail macaques chasing a woman on a scooter in the town of Lopburi, some 155km north of Bangkok. Residents barricaded indoors, rival gang fights and no-go zones for humans. Welcome to Lopburi, an ancient Thai city overrun by monkeys super-charged on junk food, whose population is growing out of control. (Photo by Mladen Antonov/AFP Photo)

This picture taken on September 9, 2021 and released from North Korea's official Korean Central News Agency (KCNA) shows a parade of “paramilitary and public security forces” to celebrate the 73rd founding anniversary of North Korea at Kim Il Sung Square in Pyongyang. (Photo by KCNA via KNS/AFP Photo/Stringer)

Models showcase collection by designer Zhang Kejia during the 2021 Kunming Fashion Week on December 15, 2021 in Kunming, Yunnan Province of China. (Photo by Li Jiaxian/China News Service via Getty Images)