Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

In this image provided by the Ministry of Defence, Prince William takes the controls of a Sea King helicopter on April 14, 2011 in Holyhead, Wales. Search and rescue co-pilot Prince William, based at RAF Valley will marry his fiancee Catherine Middleton in Westminster Abbey in London on April 29, 2011. (Photo by MoD Crown Copyright via Getty Images)

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

Aerial photography platform SkyPixel received 27,000 entries to its 2016 competition. Here are the winning shots plus some of our favourites. Here: Dam near perfect. Second prize in the same category was of the Huia Dam in Auckland, New Zealand. Hong Kong-based SkyPixel was launched in 2014. (Photo by Brendon Dixon/SkyPixel)

Photographer of the year second place. “Girl with the Violin”. Location: Colorado, US. Shot on iPhone 13 Pro. United States. (Photo by Kelly Dallas/Courtesy of the artist and IPPAWARDS)

Opposites can attract and Anzac a doe-eyed baby kangaroo has become best friends with Peggy, a tiny squint-eyed wombat. Their unlikely union developed after the pair - both orphans - shared a pouch at the Wildlife Kilmore Rescue Centre in Victoria, Australia. At just over five months old, Anzac was brought to the centre after being rescued in the Macedon Ranges. The joey is in the mother kangaroo's pouch for about eight months, depending on the species, but Anzac was abandoned a few months before he was ready to be free.

A runner in fancy dress participates in the Virgin London Marathon 2013 on April 21, 2013 in London, England. (Photo by Tom Dulat/Getty Images)

Ukraine's Ruslana performs her song Wild Dance ands wins the Eurovision Song Contest on May 15, 2004 at the Abdi Ipekci Stadium, in Istanbul, Turkey. The event – hosted by last year's winners Turkey – also celebrates the 30th Anniversary of ABBA's win. (Photo by Christopher Furlong/Getty Images)