On the morning of November 11, just before 9:30 UT, a mysterious rumble rolled around the world. The seismic waves began roughly 15 miles off the shores of Mayotte, a French island sandwiched between Africa and the northern tip of Madagascar. The waves buzzed across Africa, ringing sensors in Zambia, Kenya, and Ethiopia. They traversed vast oceans, humming across Chile, New Zealand, Canada, and even Hawaii nearly 11,000 miles away. These waves didn't just zip by; they rang for more than 20 minutes. And yet, it seems, no human felt them. Only one person noticed the odd signal on the...