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)

Uranjargal, a leader of the Mongolian neo-Nazi group Tsagaan Khass, stands next to a statue of Chingunjav, a Mongolian national hero, in Ulan Bator June 22, 2013. The group has rebranded itself as an environmentalist organisation fighting pollution by foreign-owned mines, seeking legitimacy as it sends Swastika-wearing members to check mining permits. Over the past years, ultra-nationalist groups have expanded in the country and among those garnering attention is Tsagaan Khass, which has recently shifted its focus from activities such as attacks on women it accuses of consorting with foreign men to environmental issues, with the stated goal of protecting Mongolia from foreign mining interests. This ultra-nationalist group was founded in the 1990s and currently has 100-plus members. (Photo by Carlos Barria/Reuters)

Riot police face off with demonstrators at the “Occupy Denver” camp on October 29, 2011 in Denver, Colorado. Following a march by protesters, police moved in on their encampment to tear down recently erected tents. They arrested numerous protesters, pepper-sprayed others and others reportedly fired rubber bullets at the crowd during the confrontation. (Photo by John Moore/Getty Images)

Members of the organization Witness Against Torture wear orange prison jump suits with handcuffs and a hood over their heads during a demonstration urging the government to close down the detention facility at Guantanamo Bay, in Lafayette Park outside the White House January 11, 2012 in Washington, DC. Protesters carry on a 92-hour vigil in a protest of the 10th anniversary of the arrival of the first group of detainees to arrive at the US military facility (Photo by Astrid Riecken/Getty Images)

Ground personnel tend to actress Yulia Peresild after the landing of the Soyuz MS-18 reentry capsule with herself and director Klim Shipenko of the “Vyzov” (The Challenge) film crew as well as Roscosmos cosmonaut Oleg Novitsky on board, in steppes southeast of Jezkazgan, Kazakhstan on October 17, 2021. (Photo by Sergei Savostyanov/TASS)

Peruvian surfer Carlos “Huevito” Areola rides a reed board, or “caballito” (little horse), into a wave at Sydney's Bondi Beach, February 24, 2016. Areola is part of a group of Peruvian surfers touring Australia’s east coast to promote the use of the “caballito”. The “caballito” is thought to have been invented around 3,000 BC in northern Peru. (Photo by Jason Reed/Reuters)

The city of Meroë laid undiscovered for two millennia before British archaeologist John Garstang excavated it in the early 20th century. Garstang took the radical decision to document his discoveries with photography – and immortalised an ancient world. “Meroë: Africa’s Forgotten Empire” is being shown until 14 September at Garstang Museum of Archaeology, Liverpool. Here: A group visiting the excavations at Meroë, including (from left) Midwinter Bey, director of Sudan Railways; Lord Kitchener; General Sir Francis Reginald Wingate, Sirdar of the Egyptian Army; Professor Archibald Sayce; John Garstang; and Lady Catherine Wingate, 1911. (Photo by Garstang Museum of Archaeology)

An Andean man and a woman, depicting Inca's legendary characters Manco Capac and Mama Ocllo, pose for a portrait in a Uros island at Lake Titicaca before a re-enactment in Puno November 5, 2014. The Uros islands are a group of 70 man-made totora reed islands floating on the lake, which according to Peru's tourism board iPeru is the world's highest navigable lake at over 4,000 meters above sea level. The Uros people fish and hunt, but tourism is their main source of livelihood. (Photo by Enrique Castro-Mendivil/Reuters)