What happened to Amelia Earhart? Was there really an ancient city called Atlantis? What caused the fire in the sky over Siberia in 1908? This book features 12 puzzling mysteries, some centuries old, that remain unsolved. Yet people today still wonder about them and try to find answers. Each story includes attention-grabbing photos and fascinating facts. Sidebars go beyond the basics, and prompts invite readers to think for themselves. Additional mini-stories encourage further exploration.