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)

Aisha, 15, (L) (who asked to withhold her last name), a Syrian refugee from Raqqa, waits with a fellow refugee while harvesting cannabis in the Bekaa valley, Lebanon October 19, 2015. Syrian refugees work to harvest and process spiky-leafed cannabis plants in neighbouring Lebanon’s Bekaa Valley. Often farmers of cotton and wheat back home in Raqqa province – now the de facto capital of Islamic State – the conflict in Syria drove them to seek safety in a region where Syrian migrant workers used to spend a few months a year before returning home. (Photo by Alia Haju/Reuters)

Negin Ekhpulwak, leader of the Zohra orchestra, an ensemble of 35 women, practises on a piano at Afghanistan's National Institute of Music, in Kabul, Afghanistan April 9, 2016. Playing instruments was banned under Taliban rule in Afghanistan, and even today, many conservative Muslims frown on most forms of music. Living in an orphanage in the capital, Kabul, 19-year-old Negin Ikhpolwak leads an ensemble of 35 women that plays both Western and Afghan musical instruments. In a country notorious internationally for harsh restrictions on women in most areas of life, Negin's story highlights a double challenge. (Photo by Ahmad Masood/Reuters)

Chinese artist Kong Ning walks in her costume made of hundreds of orange plastic blowing horns during her art performance raising awareness of the hazardous smog in front of the Drum tower in a historical part of Beijing on a very polluted day December 7, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance “The Orange Horns Bride Marries the Blue Sky” and presented it dressed in orange, the colour of the second highest pollution alert level issued again in Beijing as hazardous smog blankets the capital. (Photo by Damir Sagolj/Reuters)

Kenyan women protest for the right to wear whichever clothes they want, at a demonstration in downtown Nairobi, Kenya Monday, November 17, 2014. A recent incident in which a mob of men surrounded a woman and tore her clothes off, leaving her naked on the street in front of a bus stop after alleging that she was improperly dressed, is one of several such videos that have surfaced online in recent days leading to a groundswell of anger that on Monday prompted around 1000 demonstrators, including a number of men supporting the women's cause, to march through the capital and protest online using the hashtag #MyDressMyChoice. (Photo by Ben Curtis/AP Photo)

Travel photographer Amos Chapple recently crossed into Turkmenistan on a three-day transit visa and was able to photograph many of the sights and monuments in Ashgabat, the capital and largest city. Turkmenistan is a single-party country, a former Soviet state, run by a president at the center of a cult of personality.

Photo: A young couple leave the Alem Entertainment Center in Ashgabat. The current president has a history of breaking obscure records. In 2012 the wheel atop this complex was entered into the Guinness Book of World Records as the world's largest enclosed Ferris wheel. The structure was built at a cost of $90m. (Photo by Amos Chapple via The Atlantic)

A street in the Cuban capital, Havana, is home to 12 sets of twins, ranging from toddlers to senior citizens. Some say it could be something in the water. Others point to a tree with mystical significance for locals. And maybe it's just chance. Photo: In this September 29, 2013 photo, nine-year-old twin sisters Camila, left, and Carla Rodriguez pose for a portrait along their street in Havana, Cuba. 12 sets of twins live along two consecutive blocks in western Havana, ranging in age from newborns to senior citizens. “We love living on this block because we have twin friends”, said Carla. (Photo by Ramon Espinosa/AP Photo)

A boy runs as heavy rains and high waves brought by typhoon Linfa, locally named Egay, crash along a breakwater along Manila Bay at a slum area in Baseco, Tondo in Manila July 6, 2015. All shipping was ordered to remain in harbor and some flights were canceled in the northern Philippines, while schools were closed in the capital, Manila, on Monday due to flooding and landslides from a tropical storm, disaster officials said. Storm warnings were issued in at least 14 areas of the main Philippine island of Luzon as tropical storm Linfa moved slowly across the north of the Southeast Asian archipelago. It was carrying maximum wind gusts of 100 km per hour (60 mph). (Photo by Romeo Ranoco/Reuters)