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)

Anilson Costa, reveller of the annual block party “Ceu na Terra”, walks along the Santa Teresa neighborhood where the block party used to be celebrated, as Carnival celebrations have been canceled, amid the coronavirus disease (COVID-19) pandemic, in Rio de Janeiro, Brazil on February 12, 2021. (Photo by Pilar Olivares/Reuters)

A girl holds a blossom in her mouth while posing for photos under cherry blossom trees at Wuhan University on March 11, 2021 in Wuhan, China. Tourists come to view cherry blossoms at the university during the spring. Wuhan University, first founded in 1893, is widely known as one of the most beautiful universities in China. (Photo by Getty Images/China Stringer Network)

Volunteers care for burned sheeps in a field hospital established by HAYTAP (The Federation of the Animals Rights in Turkey) for animals after a wildfire at the Manavgat district of Antalya, Turkey, 09 August 2021. It is not known how many wild animals living in the forest died in the fires, but about 33,000 farm animals perished. About 30 veterinarians and hundreds of volunteers work around the clock at the field hospital. Sheep, covered in mosquito nets to protect their wounds from flies, lay there in the shade trying to recover, and various animals such as cats, dogs, owls, and cows have been treated or are still being treated there. (Photo by Erdem Sahin/EPA/EFE)

Director George Clooney reacts as he and his wife lawyer Amal Clooney arrive for a screening of the film “The Tender Bar” as part of the BFI London Film Festival, in London, Britain, October 10, 2021. (Photo by Henry Nicholls/Reuters)

A firefighter passes through fire in a firefighting drill on December 7, 2021 in Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province of China. (Photo by Zeng Peng/VCG via Getty Images)

A young macaque perches on a pole, observing nearby tourists while eating some seeds in Jigokudani Yaen-koen wild macaque monkey park on February 16, 2015 in Yamanouchi, Nagano, Japan. (Photo by Manuel Romaris/Getty Images)