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)

Take a look at this stunning photo of Tolbachik, an active volcanic complex on the Kamchatka Peninsula in far eastern Russia. Lava fountains and rivers ran through the area for months after the eruption began with the opening of two Tolbachik fissures in November of 2012. In the midst of this activity, photographers Luda and Andrey (lusika33) took a trip down to see that stunning hell valley on earth. (Photo by lusika33)

A policer officer hits a man with a baton as he tries to maintain order while migrants wait for trains at a temporary camp near Gevgelija, Macedonia, September 7, 2015. Several thousand migrants in Macedonia boarded trains on Sunday to travel north after spending a night in a provisional camp. Macedonia has organised trains twice a day to the north border where migrants cross into Serbia to make their way to Hungary. Since June, Macedonian authorities have said that more than 60,000 migrants have entered the country, and around 1,500 entered just in one day, mainly refugees from Syria. (Photo by Stoyan Nenov/Reuters)

A visitor celebrates after attending a bare hand fishing event in a frozen river during the Hwacheon Sancheoneo Ice Festival at Hwacheon-gun, Gangwon province, South Korea, 09 January 2016. The festival runs under the theme “Unfrozen Hearts, Unforgettable Memories” from 09 January to 31 January 2016. (Photo by Jeon Heon-Kyun/EPA)

A boy looks on as fire fighters try to extinguish the fire at oil wells, were set on fire by Daesh terrorists as they fled after Al Qayyarah town's cleansing from Daesh militants as the operation to retake Iraq's Mosul from Daesh continues, in Al Qayyarah Town of Mosul, Nineveh, Iraq on November 02, 2016. (Photo by Yunus Keles/Anadolu Agency/Getty Images)

Elephants are paraded in front of the Grand Palace to pay respects to the late Thai King Bhumibol Adulyadej in Bangkok on October 8, 2016. Thailand' s King Bhumibol Adulyadej died at the age of 88 on October 13 after years of ill health, ending a seven- decade reign and leaving the politically divided nation without its key pillar of unity. (Photo by Lillian Suwanrumpha/AFP Photo)

South Korean college students wearing masks hold up candles as they march after a rally calling for South Korean President Park Geun-hye to step down in Seoul, South Korea, Saturday, November 12, 2016. Hundreds of thousands of people flooded Seoul's streets on Saturday demanding the resignation of Park amid an explosive political scandal, in what may be South Korea's largest protest since it shook off dictatorship three decades ago. (Photo by Lee Jin-man/AP Photo)

Medics carry a wounded person at the scene after an attack at a popular nightclub in Istanbul, early Sunday, January 1, 2017. Istanbul Governor Vasip Sahin said that an armed assailant has opened fire at a nightclub in Istanbul during New Year's celebrations. Turkish authorities have banned distribution of images relating to the Istanbul attack within Turkey. (Photo by IHA via AP Photo)