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)

Women walk past a pile of rubbish bags on a street during a strike by garbage collectors demanding delayed salaries in Sanaa, Yemen May 8, 2017. (Photo by Khaled Abdullah/Reuters)

Women, dressed in traditional Japanese kimonos, cross a street in Kyoto, western Japan November 19, 2014. (Photo by Thomas Peter/Reuters)

A youth dives into a crater filled with water in Aleppo's al-Shaar district, in this July 10, 2014 file photo. (Photo by Hosam Katan/Reuters)

Passengers wearing protective masks travel on an over crowded train towards capital city, amid concerns about the spread of the coronavirus disease (COVID-19), in Colombo, Sri Lanka, July 8, 2020. (Photo by Dinuka Liyanawatte/Reuters)

A woman hangs red chillies to dry outside her house at Khokana village on the outskirts of Kathmandu on August 5, 2020. (Photo by Prakash Mathema/AFP Photo)

Iranian girls wearing face masks walk in Tehran, Iran, 02 November 2020. According to the Iranian Health ministry, Iran reported its highest daily COVID-19 death toll and infections by announcing 440 deaths and 8,289 new infections in past 24 hours in what appears to be a third wave of COVID-19 outbreak. (Photo by Abedin Taherkenareh/EPA/EFE)

Members of the media document a damaged train carriage extracted from a tunnel after the deadly train derailment north of Hualien, Taiwan on April 6, 2021. (Photo by Ann Wang/Reuters)