July 2021. Germany's Ahr Valley experienced one of Europe's deadliest natural disasters in decades. The Ahr River, normally calm and shallow, rose 7 meters in just a few hours during unprecedented rainfall. Entire homes were swept away. Streets transformed into violent torrents carrying cars, debris, and people. Survivors described watching helplessly as neighbors vanished into the muddy water. Emergency services were overwhelmed. Communication lines went down. By the time the waters receded, 18