Humongous Fungus

Watch out, Milwaukee. Something is growing in the woods just over, or rather under, the Wisconsin-Michigan border. It feeds off rotting organic matter and tree roots, and has been doing so for 1,500 years, making it at least half as old as a mature sequoia tree. The thing has already taken over a whopping 15 hectares (37 acres). It weighs in at somewhere between 100 and 1,000 tons, at least as big as a blue whale. And it is still growing. At its present creep, it could reach the city of beer and bratwurst in a mere 1.6 million years.

The...