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 General Atomics MQ-9 Reaper stands on the runway during “Black Dart”, a live-fly, live fire demonstration of 55 unmanned aerial vehicles, or drones, at Naval Base Ventura County Sea Range, Point Mugu, near Oxnard, California July 31, 2015. (Photo by Patrick T. Fallon/Reuters)

A child sleeps inside a makeshift hammock made of a saree which is a tradition Indian costume worn by women, along a road in New Delhi on August 19, 2021. (Photo by Sajjad Hussain/AFP Photo)

Kashmiri children play with snow on a wooden foot bridge in the interiors of Dal Lake in Srinagar on January 16, 2017. A cold wave has further tightened its grip in Jammu and Kashmir, with most places in the state recording sub-zero temperatures. (Photo by Tauseef Mustafa/AFP Photo)

Francis Sierra, 23, smokes as she competes for the longest ash during the XVIII Habanos Festival in Havana, March 3, 2016. (Photo by Alexandre Meneghini/Reuters)

The Viking longboat burns during the annual Up Helly Aa festival in Lerwick, Shetland Islands, on January 28, 2014. Up Helly Aa celebrates the influence of the Scandinavian Vikings in the Shetland Islands and culminates with up to 1,000 “guizers” (men in costume) throwing flaming torches into their Viking longboat and setting it alight later in the evening. (Photo by Andy Buchanan/AFP Photo via Getty Images)

Hindu holy men display their yoga skills before media on International Day of Yoga at the Kamakhya temple in Guwahati, Assam, India, Wednesday, June 21, 2023. The holy men from different parts of this northeastern state arrived at the temple to attend the Ambubachi festival that starts on Thursday. (Photo by Anupam Nath/AP Photo)

Aerial view of a boat working in the green water of Taihu Lake covered by blue-green algae, Wuxi city, Jiangsu province, China on May 23, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)