Coruscant is the central hub for civilization and politics, serving as the primary world for the galaxy's superpower, switching hands over thousands of years. The entire world, except for the Manarai Mountains, is completely covered in a cityscape of buildings and thousands of levels. The buildings include the domed Senate Building, the Jedi Temple, the Imperial Palace, and many others - these buildings going through many phases of destruction and rebuilding.
The weather of Coruscant is controlled by orbital mirrors and satellites, artificially simulating weather conditions, typically maintained at spring-like temperatures.
After the terraforming of Coruscant by the Yuuzhan Vong, despite attempts at restoration, pieces of the planet were corroded by organic life, covered in ivy and in states of disrepair. This was especially true in the lower levels.
As empires rise and fall, Coruscant has been the throne world for many governments and the center of many galactic conflicts.
Thousands of years before the Republic and before recorded chronology, ancient Coruscant - before the vast technology - was the place of a struggle between the tribal humans and Taungs, with the latter faction forced offworld by the victorious humans.
Around 30,000 years before the Battle of Yavin (BBY), Coruscant and her inhabitants were enslaved by the Infinite Empire, an advanced race of aliens known as the Rakata that had all but completely conquered the known galaxy. They were wiped out by a virus, retreating to their homeworld of Lehon, mostly dying out there. In their exodus, they left some of their technology behind, including the revolutionary Hyperspace drives, a crucial part of galactic civilization.
It wasn't until about 5,000 years after the defeat of the Rakata that the Galactic Republic was formed in c. 25,000 BBY. The Galactic Republic became the main government in the galaxy. The Republic and their sworn ally, the Jedi Order, became the primary authority throughout the galaxy.
In 1,000 BBY, the Republic went through what would be called the Ruusan Reformation, the result of the final battle of the New Sith Wars against the Sith. The senate was given greater power, not wanting to trust in a single man, namely a Supreme Chancellor. The armies of the Republic were lessened, as was the involvement of the Jedi Order, preventing the Jedi from acting as a military force unto themselves - as they did during the New Sith Wars.
In 22 BBY, a new threat consisting of renegade systems separating from the Republic, known as the Confederacy of Independent Systems (CIS) was out to defeat the Republic. The Republic was caught at a disadvantage to meet this threat, with no army to fight for them. However, they found that a clone army had been created under commission from a long-dead Jedi Master, master Sifo Dyas - though in reality, it was ordered by Count Dooku, who was ordered to do so by the Sith Lord, Darth Sidious. This clone army, known as the Grand Army of the Republic, was utilized in the three year fight with the Confederacy in what would be known as the Clone Wars. Near the end of the Clone Wars, Coruscant became the cite of battle, which served only as a diversion to capture Chancellor Palpatine.
Finally, the Galactic Republic would suffer a killing blow: Palpatine, revealing himself to be Darth Sidious, set string of events that led to the senate becoming distrustful of the Jedi, due to their attempted "assassination" of Palpatine. He executed Order 66, which causes clones throughout the galaxy to kill their Jedi commanders. He sent his apprentice, Darth Vader, with the 501st Legion to the very steps of the Jedi Temple, laying siege to the landmark and symbol. Palpatine disbanded the Republic, creating his own Galactic Empire. During the reign of the Empire, Coruscant was often called Imperial Center. Palpatine ruled from Coruscant for decades.
Many years later, Coruscant came under the control of the New Republic. They created a Jedi headquarters on the ruins of the destroyed temple for the reformed New Jedi Order, built from the ashes of the old Order. .
In 25 ABY (After the Battle of Yavin, 21 years after the Empire's fall), a new threat came to the galaxy: the Yuuzhan Vong, a race of formidable warriors who consider all things technology to be blasphemous to their deities, utilizing living creatures as weapons and even "starships". And so, after the New Republic ignored the Vong until it was far too late, the Vong attacked and conquered Coruscant. This was the first time in galactic history that Coruscant had been invaded and taken over through military force by another faction. The New Republic was effectively disbanded, the New Jedi Order fled Coruscant, and the Yuuzhan Vong claimed victory.
The Vong terraformed the surface of Coruscant, covering it in plant life and other biological modifications, attempting to convert Coruscant into a new "Yuuzhan'tar" (the Yuuzhan Vong homeworld).
The former members of the New Republic formed the Galactic Alliance, enlisting the help of even more systems, including the Imperial Remnant. They Alliance retook Coruscant, defeating the Yuuzhan Vong. But the damage was done: a lot the surface had been destroyed beyond repair, leaving pieces of the planet in an almost "mutated" state of biological and mechanical, especially in the lower levels, which got worse as one went deeper. During this time, the Jedi Temple was also rebuilt.
About a hundred years later, the New Empire - controlled by the Fel bloodline started by Jagged Fel - were manipulated by the One Sith into engaging in a war with the Galactic Alliance. In the process, they took Coruscant. However, Roan Fel - the Emperor of the New Empire - was betrayed by the One Sith leader, Darth Krayt, who took the throne, forcing Fel and his empire to retreat to Bastion. Thus, the Sith took control once more of Coruscant, converting the rebuilt Jedi Temple into a Sith Temple. Coruscant remained in Sith hands for ten years.
The New Empire, the remnants of the Galactic Alliance, and the New Jedi Order came together for a final attack. In the process, Darth Krayt is killed, the remaining Sith retreat offworld, and Emperor Roan Fel dies. The result is the formation of the Galactic Federation Triumvirate, consisting of the New Empire, the Galactic Alliance, and the New Jedi Order.