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)

Only the most intrepid urban explorers cross the tattered ruins of the old Iron Curtain to endure the excessive bureaucracy, military paranoia and freezing winds of the East to hunt for the ghosts of an empire. Rebecca Litchfield is one who couldn’t resist the haunting allure of the ruins of the Soviet Union.

In this January 23, 2021, file photo, a police officer detains a young woman during a protest against the jailing of opposition leader Alexei Navalny in Pushkin square in Moscow, Russia. Allies of Navalny are calling for new protests next weekend to demand his release, following a wave of demonstrations across the country that brought out tens of thousands in a defiant challenge to President Vladimir Putin. (Photo by Alexander Zemlianichenko/AP Photo/File)

Blindfolded Myanmar boys try to eat the biscuits during a fair on the occasion of the 73rd Myanmar Independence Day in Yangon, Myanmar, 04 January 2021. Myanmar, also known as Burma, was colonized by Britain in 1824 and became an independent republic on 04 January 1948. (Photo by Lynn Bo Bo/EPA/EFE)

Rep. Jason Crow, D-Colo., comforts Rep. Susan Wild, D-Pa., while taking cover as protesters disrupt the joint session of Congress to certify the Electoral College vote on Wednesday, January 6, 2021. (Photo By Tom Williams/CQ-Roll Call, Inc via Getty Images)

A dog at the Zoozashchita-NN veterinary clinic in Nizhny Novgorod, Russia on February 19, 2021. On February 13, 13 stray dogs with bright blue fur were found and caught at the Dzerzhinskoye Steklo (Dzerzhinsk Glass) factory producing acrylic glass and prussic acid in the city of Dzerzhinsk. The dogs' fur tested positive for the Prussian blue pigment; now the dogs are under supervision at the Zoozashchita-NN vet clinic in Nizhny Novgorod. (Photo by Mikhail Solunin/TASS)

People wear traditional Chinese outfits as they walk in Chinatown in Bangkok on February 11, 2021, ahead of the start of the Lunar New Year, which ushers in the Year of the Ox on February 12. (Photo by Lillian Suwanrumpha/AFP Photo)

Family members pose for photos near lava flowing from Pacaya Volcano near El Patrocinio village in San Vicente Pacaya, Guatemala, Friday, April 16, 2021. (Photo by Moises Castillo/AP Photo)