xAI just filed a $659 million building permit in Memphis, Tennessee. For a mystery building, four stories. 312,000 square feet. Right next to the most powerful AI supercomputer ever built. The documents don’t even say what it’s for. Here’s what we know. xAI already runs Colossus 2, a facility packed with 550,000 NVIDIA GPUs. It came online in January and satellite photos showed it wasn’t even close to full capacity yet. Now they’re expanding, again. This is part of something much bigger. In January, Elon Musk committed $20 billion to a third data center across the state line in Mississippi. The largest private investment in that state’s history. The goal is 2 gigawatts of AI compute power concentrated in one cluster. Enough electricity to power 1.5 million homes, all for one thing training Grok. No other company on Earth has anything like this. xAI has more GPUs at a single site than most nations have in total. ...