Video versions of my presentations are stored at: https://www.youtube.com/channel/UC4x4T-5Itm_FsR07hKJYstA/videos The oceans and seas are incredible things of beauty, with a fascinating mix of underwater gardens and marine life. Of particular importance are the stunning coral reefs, which act as a protection mechanism to coastlines and a home to an array of ecosystems. Many of them are, unfortunately, threatened due to man-made causes and in need of preservation. Here are the most beautiful in the world.