A member of the United States Naval Academy freshman class wears body armor, helmet and carries a rifle through a mud-filled ditch as part of the “Wet and Sandy” challenge during the rigorous Sea Trials May 17, 2011 in Annapolis, MD. Under strict safety supervision, about 900 freshmen, or “Plebes”, faced 14 hours of 32 rigorous physical and mental challenges during the trials, a daylong, action-oriented event modeled after the Marine Corps 54-hour Crucible and the Navy's Battle Stations. (Photo by Chip Somodevilla/Getty Images)

In this photo taken Wednesday, November 26, 2014 attack dogs and their handlers apprehend a “rhino poacher” center, after alighting from a helicopter into water, in a simulation exercise showing training at an academy run by the Paramount Group, near Rustenburg, South Africa. The course prepares canine units to find firearms or contraband, track suspects in the undergrowth and abseil in harnesses from helicopters in pursuit of poachers. Dogs and handlers learn to trust each other and fine tune a relationship balancing control and aggression. (Photo by Denis Farrell/AP Photo)

People and Nature category winner: Why did the sloth cross the road? by Andrew Whitworth (Osa Conservation and University of Glasgow), taken in Osa Peninsula, Costa Rica. “I was driving out from the Osa Peninsula, located on the southern Pacific coast of Costa Rica on a dark, stormy day. This female three-toed sloth (Bradypus variegatus) had luckily just about made it across the road, and the drivers of the Toyota on this occasion had spotted her in good time”. (Photo by Andrew Whitworth/2019 British Ecological Society Photography Competition)

Archie McQuater, 82-year-old clockmaker at Craiglea clocks, adjusts a clock face to British Summer Time (BST) on March 25, 2011 in Edinburgh, Scotland. Clocks will be put forward by one hour at 1:00 AM GMT on Sunday March 27, 2011 officially the start of British Summer Time. British Summer Time will end this year on October 30. (Photo by Jeff J Mitchell/Getty Images)

Police take part in a role play exercise as they clear a protest on top of a train during training on March 6, 2012 in Oxenhope, England. A new team of specialist officers set up to deal with searches and policing at a height, such as on top of a train, undergo training exercise in Oxenhope, West Yorkshire. (Photo by Bethany Clarke/Getty Images)

Actress Ruby Rose, left, recipient of the Stephen F. Kolzak Award, hands her jacket to presenter Taylor Swift during the 27th Annual GLAAD Media Awards at the Beverly Hilton on Saturday, April 2, 2016, in Beverly Hills, Calif. (Photo by Chris Pizzello/Invision/AP Photo)

Revellers celebrate the death of Britain's former prime minister Margaret Thatcher in Brixton, south London April 8, 2013. Margaret Thatcher, the “Iron Lady” who transformed Britain and inspired conservatives around the world by radically rolling back the state during her 11 years in power, died on Monday following a stroke. She was 87. (Photo by Olivia Harris/Reuters)

Army paratroopers carry the casket of Private Howard at the Wellington Cathedral on December 21, 2010 in Wellington, New Zealand. Private Howard was serving with the British army when was killed by friendly fire from a US Air Force plane in Helmand Province, Afghanistan earlier this month. Private Howard is the fifth NZ-born soldier to be killed in action in Afghanistan. (Photo by Marty Melville/Getty Images)