A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

The CBRE Urban Photographer of the Year competition – now in its ninth year – encourages professional and amateur photographers to capture cities at work. Here: Dog Walker – 15:00. The competition allows photographers to enter up to 24 images, one representing each hour of the day. (Photo by Johanna Siegmann)

“One talented photographer has managed to capture these jaw-dropping images that show off the beauty of the surf and the art hidden in the waves. Kenji Croman has a deep passion for bodyboarding and photography and was inspired to combine the two after growing up in Hawaii”. – Caters News. (Photo by Kenji Croman/Caters News)

When Stu Thomson (Cut Media) and Danny MacAskill approached us (Santa Cruz Bicycles) with the idea of being the first to tackle the Black Cuillin ridge on a bicycle, we were in from the start. Located on the Isle of Skye (Danny’s home on the west coast of Scotland) the ridge is infamous for its jagged trails, wild weather and dramatic climbing route up the “Inaccessible Pinnacle”.

These beautiful shots may look like works of modern art – but they are actually close-ups of chemical reactions. The works were snapped with the help of a group of scientists from the University of Science and Technology of China (USTC) in Anhui, China. Here: Zinc reacting with lead nitrate in a soft gel to form lead crystals. (Photo by Yan Liang/Caters News)

It would seem to be something you'd see only in a cartoon or at a Phish concert, but according to park rangers in New South Wales, Australia, dozens of giant, fluorescent pink slugs have been popping up on a mountaintop there. The eight-inch creatures have been spotted only on Mount Kaputar, a 5,000-foot peak in the Nandewar Range in northern New South Wales. Scientists believe the eye-catching organisms are survivors from an era when Australia was home to rainforests. A series of volcanoes, millions of years of erosion and other geological changes “have carved a dramatic landscape at Mount Kaputar”, the park service wrote on its Facebook page, and unique arid conditions spared the slugs from extinction. (Photo by Michael Murphy/AFP Photo/NSW Environment Office)

An election poster calling for the legalisation of marijuana and featuring internet meme “Grumpy Cat” hangs outside the Pirate Party's campaign headquarters in Berlin on August 16, 2013. The Pirates, who to everyone's surprise were elected into Berlin's regional parliament in September 2011, are trying to capitalise on their recent electoral gains in upcoming parliamentary elections, running on a platform of transparency in government. Germany goes to the polls on September 22, 2013. Placard reads: “Hurry up, my dope is everything”. (Photo by John Macdougall/AFP Photo)

Maudy – Kalulushi, Zambia. Maudy was born in a hut in a small village close to Kalulushi, in Zambia. She grew up playing in the street with the other children in the village, who all attend the same school, where students ages 3 to 10 years old are in the same class. The village has no shops, restaurants or hotels, and just a few children are lucky enough to have toys. Maudy and her friends found a box full of sunglasses on the street, which quickly became their favorite toys. “Toy Stories” project. (Photo and caption by Gabriele Galimberti)