Yavin 4

Yavin 4 is one of the many moons of the gas planet Yavin in the Star Wars universe. It was home to the Rebel Alliance's main military base in Star Wars Episode IV: A New Hope. The Rebels established their base in the ancient Massassi ruins found in its lush jungles following the destruction of their previous base on the planet Dantooine. The Galactic Empire sought to use its new space station super-weapon, the Death Star, to destroy the small jungle moon and crush the Rebellion. A small force of X-Wing and Y-Wing starfighters were sent to destroy the Death Star, but most were killed in the attack. With seconds remaining and the timely assistance of his friend Han Solo, Luke Skywalker was able to fire a proton torpedo into a small thermal exhaust port along the Death Star's equatorial trench, thus destroying the station and saving Yavin 4. A great ceremony was held following the Death Star's destruction, where Princess Leia bestowed medals of honor to Luke Skywalker and Han Solo, along with his Wookiee co-pilot, Chewbacca.

This battle became known as the Battle of Yavin, and its date is used as a place-marker for events in the expanded Star Wars universe. Events before the Battle of Yavin are marked by BBY, and events that occur after are marked by ABY.