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 team of expert cavers and photographers had been exploring caves in the Chongquing province of China – when they were amazed to discover the entrance to a hidden cave that was previously undiscovered. And they were stunned when they managed to enter the ginormous cave – and found that it was so large there was even a cloud inside it – a cave so large it has its own weather system. Photographer and caver Robbie Shone, from Manchester, was part of a team of 15 explorers on a month-long expedition who stumbled across the natural wonder”. – Caters News

Reuters photographer Lucy Nicholson documented some of the migrant communities that live in Los Angeles. Los Angeles is a culturally thriving city and one of the most ethnically diverse in the United States, with a population that is 48.5 percent Latino and 11.3 percent Asian, according to a 2010 census. Immigration has become a hot button issue ahead of U.S. midterm elections on November 4, and despite arguments from the White House that legal migration benefits businesses, a recent opinion poll found most Americans believe migrants place a burden on the economy. (Photo by Lucy Nicholson/Reuters)

Juri Mitomi, 20, holds a cigarette after a Coming of Age Day celebration ceremony at an amusement park in Tokyo January 12, 2015. According to a government announcement, more than 1.2 million men and women who were born in 1994 marked the coming of age this year, an increase of approximately 50,000 from last year. The increase is also the first since 1995. (Photo by Yuya Shino/Reuters)

Intrigued by photographing time, Singapore-based photographer Fong Qi Wei created single, composite pictures from a sequence of images spanning 2-4 hours. He concentrated on capturing sunrises and sunsets as they evolved over different landscapes, seascapes, and cityscapes. He then digitally stitched the images together to get a snapshot of time passing over the scene for his series “Time is a Dimension”. “Most paintings and photographs are an instance of time”, Wei explained in his artist’s statement. “That’s not the way the world works. We experience a sequence of time, and that’s why a video is somehow more compelling than a freeze frame”. (Photo by Fong Qi Wei/Thoughtful Photography)

Thanks to plenty of salt minerals and heavy elements in the soil, the Dallol volcano in Ethiopia produces brilliantly colored pools of water at the top of its caldera. And, as if to add greater effect to the already stunning sights, the volcano stands apart from the salt plains around it like an island. This hotspot was created through phreatomagmatic eruptions caused by magma interacting with water, and was further altered due to the presence of salt water. (Photo by Francisco Pandolfo/Caters News)

Four hundred buyers from around the world join 260 diamond manufacturing and trading firms on International Diamond Week as some 1,500 people are expected to trade more than billion of polished diamonds this week in Ramat Gan, Israel on February 16, 2016. The Israel Diamond Exchange is considered the most secure in the world, covering an area of 100,000 square meters with 3,500 bourse members. (Photo by Nir Alon via ZUMA Wire)

People sit on a cart with a camel tied to it during “Temeenii bayar”, the Camel Festival, in Dalanzadgad, Umnugobi aimag, Mongolia, March 6, 2016. On the steppes of the Gobi Desert, the crowd urges on Bactrian camels laden down with all that's needed to build and live in a traditional Mongolian tent. Guinness World Records classes the 15 km race thatÕs part of the two-day festival as the largest camel race in the world, drawing 1,108 participants. The winning camel romped home in 35 minutes and 12 seconds, according to the records website. (Photo by B. Rentsendorj/Reuters)