Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)

These unique photos capture the moment a boy has his teeth picked clean by amazing underwater shrimp. These fascinating creatures spend their lives diving inside the mouths of fish to remove the parasites that lurk there. Russell Laman imitated the behaviour of the surrounding fish swarm to entice the cleaner shrimp into his mouth whilst snorkelling with his father Tim Laman in Bali, Indonesia. The 13-year-old queued with the waiting fish and then opened his mouth when the shrimps came near. (Photo by Tim Laman/Caters News)

A Sri Lankan activist, who wrapped himself with fire crackers, walks in Colombo on July 23, 2014 to symbolically demonstrate against people burned during Anti-Tamil riots on the island thirty-one years ago. Official accounts placed the death toll at 400 while human rights activists put the toll at thousands. (Photo by Ishara S.Kodikara/AFP Photo)

A group of surfers ride the Bore Tide at Turnagain Arm on July 15, 2014 in Anchorage, Alaska. Alaskas most famous Bore Tide, occurs in a spot on the outside of Anchorage in the lower arm of the Cook Inlet, Turnagain Arm, where wave heights can reach 6-10 feet tall, move at 10-15 mph and the water temperature stays around 40 degrees farenheit. This years Supermoon substantially increased the size of the normal wave and made it a destination for surfers. (Photo by Streeter Lecka/Getty Images)

The main feature of the Mitsuyama Taisai Festival, three 18 meters tall “mountains”. are displayed at the Itate Hyozu Shrine on March 31, 2013 in Himeji, Japan. The festival is held once in 20 years since 1593, Priests of Itate Hyozu Shrine welcome to all the gods across the country for top of the three mountains and treat with food seven days from today as to pray for peace and prosperity. (Photo by Buddhika Weerasinghe)

Protesters wearing masks perform during anti-austerity and anti-graft protests in Ljubljana, Slovenia, on January 11, 2013. More than 5,000 Slovenians gathered in the center of Ljubljana on Friday to protest against a corruption scandal that threatens to bring down the government. Slovenia's anti-corruption commission said earlier this week that Prime Minister Janez Jansa had been unable to explain the source of some of his income in recent years. (Photo by Srdjan Zivulovic/Reuters via The Atlantic)

Serge Huguenin of the Blondeau foundry takes the newly melted bell out of the mould in La Chaux-de-Fonds, Switzerland January 21, 2016. At this year's Summer Olympics in Rio de Janeiro, no matter how elaborate the opening ceremony or how sophisticated the live broadcasts, the final lap of athletics races will be announced the traditional way by ringing an old-fashioned bell. Omega, the official timekeeper of the event, has ordered 21 bells, forged almost entirely by hand by Blondeau's Bell Foundry in the Jura Mountains in Switzerland. Each last-lap bell is branded with the RIO 2016 logo and circled with the words “2016 GAMES OF THE XXXI OLYMPIAD”. (Photo by Denis Balibouse/Reuters)

In this January 31, 2014 file photo released by the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), shows residents of the besieged Palestinian camp of Yarmouk, queuing to receive food supplies, in Damascus, Syria. That year, the U.N. was able to deliver food to about five percent of people in besieged areas including Yarmouk, while today estimates show the organization is reaching less than one percent. (Photo by UNRWA via AP Photo)