Grenada has an underwater sculpture park and there are also some in Mexico. http://www.telegraph.co.uk/earth/environment/3538787/Underwater-sculpture-park-off-Grenada-is-stunning-and-unique.html
http://www.underwatersculpture.com/pages/gallery/jardinera-esperanza.html view the photos from left to right in order to see how "The Gardener" in Mexico is a terrific example of how a sculpture can evolve to enhance the underwater landscape.
Besides the sea life , they attract not only divers, but snorkelers as well in shallower waters. Win win on for an island which does not always have great underwater visibility!