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 Afghan man works at a traditional yarn factory in Heart province, Afghanistan July 28, 2015. (Photo by Mohammad Shoib/Reuters)

A man wearing a water-filled helmet in which a goldfish swims performs an act titled “Aquaman” during the Night Festival 2016 in Singapore, 20 August 2016. The ninth edition of the festival will run from 19 to 27 August and features installations and performances by a range of international and local artists. (Photo by Wallace Woon/EPA)

Muay Thai boxer Nong Rose Baan Charoensuk, who is transgender, trains at a gym in Buriram province, Thailand, July 3, 2017. Born Somros Polchareon, Rose said she identified as a woman at an early age and began wearing makeup and a sports bra in the ring.(Photo by Athit Perawongmetha/Reuters)

Elementary school sumo wrestlers compete in the sumo ring during the Wanpaku sumo-wrestling tournament in Tokyo, Japan July 30, 2017. (Photo by Kim Kyung-Hoon/Reuters)

Women jump into the water during a traditional New Year bath in the Adriatic sea in Portoroz, Slovenia on January 1, 2018. (Photo by Jure Makovec/AFP Photo)

A reveler in costume laughs during the “Cordao do Boitata” street party in Rio de Janeiro, Brazil, Sunday, February 24, 2019, one of the many parades before the official start of Carnival on March 1. (Photo by Leo Correa/AP Photo)

This screengrab from Thai TV Pool video taken on May 1, 2019 shows a ceremony in which Thailand's King Maha Vajiralongkorn “legally married” Suthida Vajiralongkorn na Ayudhya in Bangkok. Thailand announced on May 1, 2019 that King Maha Vajiralongkorn's long-time consort had become his fourth wife, bestowed with the title Queen Suthida – a surprise move just days before his coronation. (Photo by Bureau of the Royal Household via Reuters)