An employee of the National Park Service takes a selfie with President Barack Obama, left, in the background meeting with the crowd after a tour of Everglades National Park on Earth Day, Wednesday, April 22, 2015, in Florida. Obama used the visit to warn of the damage that climate change is already inflicting on the nation's environmental treasures. (Photo by Lynne Sladky/AP Photo)

President Barack Obama watches as Joey Hudy (L), 14, from Phoenix, Arizona pumps the Extreme Marshmallow Cannon he invented, while touring student science fair projects on exhibit in the State Dining Room at the White House February 7, 2012 in Washington, DC. Obama hosted the second White House Science Fair celebrating the student winners of science, technology, engineering and math (STEM) competitions from across the country. (Photo by Molly Riley-Pool/Getty Images)

Clowns sit in the pews and hold hands across the aisle of the All Saints Church during the Grimaldi clown service in Dalston, north London, February 7, 2016. The Clowns International 70th annual service brings together professional clowns from Britain and Europe in a service of remembrance to the famous British clown Joseph Grimaldi, who died in 1837. (Photo by Peter Nicholls/Reuters)

Vapour bounced off the wings of the Lockheed Martin F-35 Lightning II as it sped over the Welsh mountains at a swift 575mph on February 10, 2022. The jet was taking part in a low-level training exercise through the Mach Loop – a series of valleys in North Wales. (Photo by Thomas Winstone/News Images)

Veterinarians and biologists from the Quito Zoo and the Andean Condor Foundation fit a tracking collar that juvenile Andean bear Tupak will wear for the next four years, prior to his reintroduction into the wild, after the bear's life was deemed in danger due to proximity to humans, in Quito, Ecuador on March 31, 2024. (Photo by Karen Toro/Reuters)

The faces of war have been brought back to life after a series of World War One photographs were expertly colourised. The black and white snaps were painstakingly restored and colourised by photographer Mario Unger (53) from Rotenturm, Austria. Here: One image shows an unidentified American soldier posing with a pistol, helmet, and Iron Cross medal taken from a German soldier, 1918. (Photo by Mario Unger/Mediadrumworld)

In this April 4, 2017 photo keeper German Alonso straps a leg prothesis to on the left leg of secretarybird Soeckchen (Sagittarius seprentarius) at the bird park in Walsrode, northern Germany. The prothesis was made in a 3D-printer after his left leg was amputated. (Photo by Philipp Schulze/DPA via AP Photo)

In this photo taken Wednesday, March 8, 2017, a woman herder sits with her goats in a remote desert area near Bandar Beyla in Somalia's semiautonomous northeastern state of Puntland. Somalia has declared the drought a national disaster, part of what the United Nations calls the largest humanitarian crisis since the world body was founded in 1945, and with animals being central to many the drought threatens their main sources of nutrition and survival. (Photo by Ben Curtis/AP Photo)