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.

A young couple rest on a bench, as a street actor wearing an Angel costume speaks on the phone in Nikolskaya street near the Kremlin in Moscow, Russia, Wednesday, March 31, 2021. (Photo by Alexander Zemlianichenko/AP Photo)

Relatives wearing personal protective equipment (PPE) mourn a man, who died from the coronavirus disease (COVID-19), during his funeral at a crematorium in New Delhi, India on April 21, 2021. (Photo by Adnan Abidi/Reuters)

Children with painted faces in the art of the bahurupi tradition in Bardhaman, India on April 24, 2021. Impersonators family where their generations are engaged in making face painting and can easily metamorphose into different characters during a performance, as per different Traditional & Tribal myth which is the main earning source for their family. (Photo by Avishek Das/SOPA Images/Rex Features/Shutterstock)

A woman leaps while arriving to greet a loved one during CLEAR Connects: A Day of Families, a mass reunion event, at MetLife Stadium in East Rutherford, New Jersey, U.S., May 6, 2021. (Photo by Brendan McDermid/Reuters)

Two drivers get into a fight while waiting in line at a gas station amid fuel shortages in Knightdale, North Carolina, May 10, 2021. (Photo by @shaaddeez/Instagram via Reuters)

A man takes photos of a high tide seen in the Bay Of Bengal before Cyclone Yaas arrives in Digha, 205km South of Kolkata, Eastern India, 25 May 2021. (Photo by Piyal Adhikary/EPA/EFE)