This document provides an introduction to gravitational waves, including a brief history of their prediction and discovery. It describes their origin and how the Laser Interferometer Gravitational-Wave Observatory (LIGO) detects them using highly sensitive laser interferometers located in Hanford, Washington and Livingston, Louisiana. The document notes that detecting gravitational waves could provide insights into the formation of black holes, test theories like the Big Bang theory, and may one day enable time travel.