epa05346453 A handout picture made available by NASA on 05 June 2016 shows an image taken by an astronaut aboard the International Space Station (ISS) using powerful lens to photograph three reefs of Australia's Great Barrier Reef, seen from space, 15 October 2015. The photo area spans about 15km of the 2,300km reef system. Reefs are easy to spot from space as the iridescent blues of shallow lagoons contrast sharply with the dark blues of deep water. The Great Barrier Reef is the largest reef system on Earth, with more than 3,000 separate reefs and coral cays. It is also one of the most complex natural ecosystems, with 600 types of corals and thousands of animal species from tiny planktons to whales.  EPA/NASA  HANDOUT EDITORIAL USE ONLY *** Local Caption *** 52804080
Australia's first underwater hotel suites are located on the Great Barrier Reef, with the world's largest coral reef systemhere seen from space. EPA

Australia's first underwater hotel opens, with views of the Great Barrier Reef