On June 30, 1908, a 15-megaton explosion devastated 800 square miles of Siberian forest, yet left no impact crater. This mystery, known as the Tunguska Event, remained largely uninvestigated until Leonid Kulik’s 1927 expedition, which concluded that a mid-air explosion had occurred. While fringe theories suggest UFO crashes or Tesla’s "death ray," scientific consensus favors an atmospheric airburst caused by a stony asteroid or comet. Today, it serves as a critical "cosmic wake-up call" regarding Earth’s vulnerability to future impacts.