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)

These spectacular images of the universe are the finalists in the 2016 CWAS “David Malin” awards. The annual competition, which celebrates the best astronomy images taken by Australian photographers, is part of AstroFest 2016. The winners will be announced on 16 July. An associated exhibition opens the following day at the CSIRO Parkes Observatory visitors centre, and a second exhibition will also travel to selected venues around Australia. Here: Mars and its Rival Antares and the Rho Ophiuchi cloud complex. (Photo by Phil Hart/CWAS/The Guardian)

Cast member Charlize Theron attends the “Atomic Blonde” World Premiere at Stage Theater on July 17, 2017 in Berlin, Germany. (Photo by Alamy Stock Photo)

Racegoers during Ladies Day of the 2018 Cheltenham Festival in Cheltenham, England on March 14, 2018. (Photo by Graham Stone/Rex Features/Shutterstock)

“Don't Leave Any Food On Your Plate”. The giraffes at Nairobi's Giraffe Manor are totally at home with humans. They will eat out of your hand, or even off your plate. Photo location: Giraffe Manor, Nairobi, Kenya. (Photo and caption by Gavin Werbeloff/National Geographic Photo Contest)

Juno, a Beluga whale, greets a young viewer at the Mystic aquarium in Connecticut, USA on December 5, 2015. (Photo by Tim Clayton/Corbis)

When Colin Garratt went to photograph the traditional sentinels of the British countryside, he found they ranged from the dapper to the downright sinister. “They are not from the anaesthetised world of the craft fair”, says Colin Garratt, “but are the direct descendants of the ancient spectres which have haunted the landscape for centuries”. The Scarecrow Exhibition is at Geddes Gallery, London, from 25 to 30 March. (Photo by Colin Garratt)