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 local boy plays football on Iracema Beach on June 11, 2014 in Fortaleza, Brazil. (Photo by Robert Cianflone/Getty Images)

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)

An Afghan man rides on his donkey, holding balloons for sale during Newroz Day celebrations, a festival marking their spring and new year, in Kabul, Afghanistan March 21, 2017. (Photo by Omar Sobhani/Reuters)

Japanese chorus girls appear to be drilling in military tactics atop their theater building as they perform salutes, June 30, 1937. The officer is from the Japanese regular army and says the girls display more rhythm in their drills than do the regular troops. (Photo by AP Photo)

Family members pose for photos near lava flowing from Pacaya Volcano near El Patrocinio village in San Vicente Pacaya, Guatemala, Friday, April 16, 2021. (Photo by Moises Castillo/AP Photo)

A Syrian Kurdish ballet dancer performs in an empty market during a lockdown to curb the spread of the Covid-19 coronavirus in Syria's northeastern city of Qamishli on April 7, 2021. (Photo by Delil Souleiman/AFP Photo)