At 7:59 a.m. on December 26, 2004, a powerful earthquake struck beneath the Indian Ocean. For 10 minutes, Earth’s crust—or rocky outer layer—shifted and shook, pushing up about 30 cubic kilometers (7.2 cubic miles) of seawater. The movement created waves that spread out in all directions. Two hours later, these waves reached the island of Phuket (pooh-KET), Thailand. As the surging water met the shallow seafloor around the island, the waves got bigger and bigger. No one on Phuket’s Mai Khao Beach realized a tsunami was headed their way—except for 10-year-old Tilly Smith, who immediately recognized the signs of an incoming disaster.