When you think of the largest living organisms on Earth, you might imagine a massive whale, a giant redwood tree, or perhaps an enormous coral reef. But one of the planet’s largest known organisms is far less noticeable; it is a fungus growing mostly underground in Oregon, USA . Image from www.planet-wissen.de Known as the “Humongous Fungus,” this extraordinary organism belongs to the species Armillaria ostoyae . Scientists discovered that its underground network covers an astonishing more than 2,300 acres , making it roughly the size of 1,600 football fields ! Image from commons.wikimedia.org But how can a fungus become so enormous? The answer lies beneath the forest floor. What we commonly recognize as mushrooms are actually only the visible reproductive structures of the fungus. Most of the organism consists of a vast network of thread-like structures called mycelium , which grow through soil and around tree roots. The Humongous Fungus is believed to have spread g...