Billionaire investor Jeremy Grantham, who predicted the dot-com crash and 2008 housing collapse, warns the AI bubble is the largest in American history and will burst within weeks to years. He reveals exactly how to protect your money, why house prices need to fall 30%, and why environmental toxins are crashing sperm counts toward zero by 2045. The AI bubble is the biggest investment bubble in American history, with a 70% stock decline not unprecedented; Japanese markets took 35 years to recover after their 1989 bubble burst.