Great Barrier Reef, Australia

Officially the largest reef system on earth, the Great Barrier Reef has almost 3,000 reefs encompassed within the 2,600 kilometre area of land that it covers.
Although the Great Barrier Reef is clearly visible from space, it is when looking at it from underneath water when it truly appears to be beautiful and somewhat magical.  Over 1,500 types of fish call the Great Barrier Reef home and in excess of 400 types of coral can be viewed in the area, meaning if you get chance to visit the area, you should make sure that you take along an underwater camera.