The Great barrier reef
The Great Barrier Reef is the largest reef system in the entire world. There are over 1500 diferent species of fish, 330 species of ascidians, and 215 species of birds that live there. There are over 900 islands and it generates about $4 to 5 billion in AU currency a year. it is so big it can be seen from space!
Ring of fire
The Ring of Fire is made up of 452 or 75% of the world's volcano. 90% of all earthquakes actually happen in the Ring of Fire. The Ring of Fire is very dangerous due to all the volcanoes there are. One of the volcanoes that is very well known is Mount St. Helens shown below.
The Mariana Trench extremely deep; 11,035 meters,36204.068 ft, and 6.8568311 miles below sea level. In 1960 the Mariana Trench was explored by the U.S. Navy Trieste; it took nearly 5 hours to desent nearly 7 miles or (11 km) down.