What is the World's Largest Living Organism?

Not a whale or a tree... 

The largest living organism is the honey fungus (Armillaria ostoyae). The area covered by the honey mushroom is, rather, 965 hectares in size. In other words, 9,650,000 m2. Based on today's growth rate, it is estimated to be 2400 years old. But it is also thought he may be 8650 years old. Honey mushrooms are connected to each other by lacing structures called rhizomorphs and are considered to be a single organism. The largest honey fungus inhabits the Blue Mountains in Oregon (USA).