A reef shell lies on a beach as the sun sets on Lady Elliot Island located north-east of the town of Bundaberg in Queensland, Australia, June 10, 2015. UNESCO World Heritage delegates recently snorkelled on Australia’s Great Barrier Reef, thousands of coral reefs, which stretch over 2,000 km off the northeast coast. Surrounded by manta rays, dolphins and reef sharks, their mission was to check the health of the world's largest living ecosystem, which brings in billions of dollars a year in tourism. Some coral has been badly damaged and animal species, including dugong and large green turtles, are threatened. UNESCO will say on Wednesday whether it will place the reef on a list of endangered World Heritage sites, a move the Australian government wants to avoid at all costs, having lobbied hard overseas. Earlier this year, UNESCO said the reef's outlook was “poor”. (Photo by David Gray/Reuters)

The British Breitling Wingwalkers, Danielle Hughes and Emily Guilding, soar above the Palm Jumeirah in Dubai at 1,500 feet (460 meters) in excess of 100mp/h, ahead of their Dubai debut performance at the 2014 UIM Skydive Dubai XCAT World Powerboating Series, on Saturday, 13th December 2014. The British team is the only aerobatic formation display team who employ full time wingwalkers and fly their two Breitling-liveried 1930's Boeing Stearman bi-planes at Air Shows and major sporting events around the world. (Photo by Katsuhiko Tokunaga/Breitling via AP Images)

Workers transport a model of a dinosaur at the exhibition “World of Dinosaurs” at a former lignite surface mining area in Grosspoesna near Leipzig, central Germany, Wednesday, October 29, 2014. A 100-foot long statue of a dinosaur had to be moved Wednesday because German authorities had deemed it a safety risk. Officials feared the sculpture could cause traffic accidents by distracting drivers on a nearby highway. The reptile, one of 50 species on show in the World of Dinosaurs exhibit near Leipzig, was moved to a less conspicuous position further from the road. (Photo by Jens Meyer/AP Photo)

They say a picture is worth a thousand words, and these striking images of 2017 are no exception. The photo highlights include incredible snapshots of the natural world as well as some awesome animal and human encounters. The vibrant gallery also shows thrill-seekers pushing themselves to the limit with breathtaking stunts captured in perfect clarity. The pictures have been taken by a host of photographers from around the world. Here: The two lion cubs singing their hearts out at Antelope park in Zimbabwe. (Photo by David Jenkins/Caters News Agency)

Technical staff take shelter as a helicopter takes off prior to the Nendaz Freeride skiing and snowboard competition, a Freeride World Tour Qualifier (FWQ) event, on the Mont Gond in Nendaz, Switzerland on March 21, 2018. (Photo by Valentin Flauraud/EPA/EFE/Rex Features/Shutterstock)

Times Square was one of many NYC locations where thousands filled the crossroads of the world to celebrate the Biden/Harris election win over Donald Trump on Saturday, November 7, 2020. This couple was thrilled with the news reenacting the famous sailor nurse WW2 victory in Times Square kiss. (Photo by Michael Nigro/Pacific Press/Rex Features/Shutterstock)

A leg of a “diablito” frog (Oophaga sylvatica) is photographed in a laboratory at a laboratory in the zoo of Cali, Colombia, on July 19, 2019. Colombia is the second country with the largest number of amphibians in the world after Brazil. More than 40% of amphibian species worldwide are in danger of extinction. (Photo by Luis Robayo/AFP Photo)

A protester wearing a bra and with a message written on her chest can be seen during the first of hundreds of womens' marches organized around the world in a show of disapproval of U.S. President Donald Trump in Sydney, Australia, January 21, 2017. (Photo by Dan Himbrechts/Reuters/AAP)