Liberation of Bespin

The Liberation of Bespin was a battle that took place shortly before the destruction of the Death Star in 0 BBY. During this battle, Rebel Alliance forces attempted to destroy Imperial generators that blocked Rebel ships from escaping. The Alliance ended up succeeding in their plans, going on to destroy the first Death Star.

History
After the Empire's embarrassing defeat at Tatooine, Alliance forces moved to rescue their fellow soldiers trapped on Bespin. 12 Imperial Star Destroyers, including the Sentinel and Victory, were stationed above Cloud City. The Alliance's goal was to destroy generators creating a gravitational pull around the planet.

Illegal bombs were planted on said generators. Rebel infantryman Hekter Stag was reported as acquiring these detonators months earlier in the underlevels of Coruscant. The bombs' dealer reportedly went missing after that, though most agree he was taken into Imperial custody for illegal armaments dealing.

48 civilians were caught in the crossfire, though none were killed. An estimated 150-160 Imperial soldiers were killed, and 190-200 Rebel soldiers were killed.

Aftermath
After the GR-75 transport known as the Deliverance escaped Imperial hands, it continued on to the Death Star, leading to the superweapon's destruction