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)

An Indian Hindu married woman offers prayers during Karva Chauth festival in Jammu, India, Sunday, October 24, 2021. Hindu married women decorate their hands with henna, wear colorful bangles and observe a fast to pray for the longevity and well being of their husbands during this festival. (Photo by Channi Anand/AP Photo)

Kyla Drumm, 5, waits after receiving the Pfizer-BioNTech coronavirus disease (COVID-19) vaccine in Skippack, Pennsylvania, U.S., November 3, 2021. (Photo by Hannah Beier/Reuters)

A masked protester talks to a soldier during clashes after the funeral of Brig. Gen. Wissam al-Hassan October 21, 2012. Lebanese soldiers fired guns and tear gas to push back hundreds of protesters who broke through a police cordon and tried to storm the government headquarters in Beirut. (Photo by Hussein Malla/Associated Press)

New York Sports Club Gets In The Election Spirit With Hillary Clinton And Donald Trump Boxing Inspired Class on October 27, 2016 in New York City. (Photo by Thos Robinson/Getty Images for DKC for New York Sports Clubs)

Runners gather at the start line for the annual “Santa Speedo Run”, a charity race through the streets of the Back Bay neighborhood of Boston. (Photo by Gretchen Ertl/Reuters)

The provincial highest chimney collapses as it is demolished by explosives in Shenyang, Liaoning province, April 28, 2014. The 150-metre-high chimney used to be part of a local heating factory, according to local media. (Photo by Sheng Li/Reuters)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)