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)

Deputy community chief of Yeneka village Douglas Oguta poses for a portrait in his home on the outskirts of the Bayelsa state capital, Yenagoa, in Nigeria's delta region October 8, 2015. Tensions are building in the swampland of the Niger Delta as an amnesty that aimed to bring stability to Nigeria's volatile southern region is due to expire at the end of the year. While the region's towns and cities are mostly calm, local residents say kidnappings and armed robberies are on the increase in the mangrove swamps, where most oil wells are located. (Photo by Akintunde Akinleye/Reuters)

In this photo taken late Thursday, May 7, 2015, a prison guard, left, and seated inmates cast shadows on a wall while waiting for the beginning of a rock concert by Romanian band Pro Musica, inside the Popa Sapca jail in Timisoara, western Romania. (Photo by Adi Piclisan/AP Photo)

Now celebrating its 40th year, Nikon Small World is widely regarded as the leading forum to recognize proficiency and photographic excellence of photography taken under the microscope. To select the winners, competition judges analyzed entries from all over the world covering subjects ranging from chemical compounds to up-close-and-personal looks at biological specimens. The 2014 winners will be revealed on October 30th. In 2014, the competition received over 1,200 entries from more than 79 countries around the world. (Photo by Dr. Igor Robert Siwanowicz/Nikon Small World 2014)

A goose has terrorized students at the University of Warwick, Coventry, UK, on May 22, 2013. The bird built its nest near a block of student apartments and attacks anyone who goes near the nest. (Photo by Caters News/The Grosby Group)

An Iran fan attends the Russia 2018 World Cup Group B football match between Morocco and Iran at the Saint Petersburg Stadium in Saint Petersburg on June 15, 2018. (Photo by Dylan Martinez/Reuters)

Model mum Valeria Garcia walks Marta Jakubowski's SS19 show wearing world first silent wearable breast pump: Elvie Pump at BFC Show Space on September 14, 2018 in London, England. (Photo by Eamonn M. McCormack/Getty Images for Elvie)

As the world marks the International Day of the Girl Child, women's rights activists point to progress on a wide array of issues but say more needs to be done to protect girls from child marriage, sexual assault and other forms of exploitation. Here is a selection of pictures showing the daily lives of girls across the globe, all taken by female Associated Press photojournalists. Here: In this December 14, 2015, file photo, a young clown rides in the back of a car following a procession to the Basilica of Our Lady of Guadalupe in Mexico City. Hundreds belonging to various clown associations made their annual pilgrimage to the Basilica to pay their respects to the Virgin of Guadalupe, Mexico's patron saint. (Photo by Rebecca Blackwell/AP Photo)