Ancient refueling spires and loading docks reached out from the native soil and some built in the upper atmosphere. In between these ports, massive vertical cities grew. The urban areas on Nar Shaddaa were known as vertical cities since new layers of housing and entertainment buildings were built on top of older layers, like Coruscant and Taris.
While much of Coruscant was filled with gleaming apartments and well-maintained skywalks, the entire moon that was Nar Shaddaa was dominated by decaying urban landscape and congested, polluted cities. The moon was protected by planetary shields. Anything illegal elsewhere could be bought and sold on Nar Shaddaa, and many young smugglers, pirates and criminals started their careers on the Smugglers' Moon. Various sections of Nar Shaddaa were controlled by the Hutts and other criminal organizations.
Despite the criminal activities on the Smuggler's Moon, it was known that many of the galaxy's most advanced technologies were actually developed on Nar Shaddaa. Corporations that wanted to avoid regulations that prohibited testing often developed such dangerous and even valuable technology within the lower levels of the city of the moon.
When the Hutts left their homeworld of Varl, they displaced the Evocii, native to Nal Hutta, to Nar Shaddaa in 15,000 BBY and immediately destroyed the remaining Evocii agriculture after the Evocii's eviction from their own homeworld. Eventually the moon was annexed by the Hutts, who started to force the Evocii into slave labor, building spaceports and docking bays across its surface, some stretching out into orbit. Although the moon's urbanized construction had just started, it quickly began to prosper, along with Nal Hutta.
In a short time, the moon was completely urbanized, and the Evocii were finally free since their work was complete. However most had died off during the construction and the few that remained, took refuge in the Undercity. Unfortunately the Evocii began to mutate into unwholesome savages due to various technologies practiced in the moon's undercity. It rivaled the galactic capital Coruscant as an important center of interstellar trade and continued to grow. In 4,000 BBY when the trade lanes shifted, Nar Shaddaa and its planet became obsolete and were eventually abandoned by the Republic.
Nar Shaddaa became a criminal haven and gained a reputation of being the center of illegal operations in the galaxy, earning the moniker "The Smugglers' Moon". Now distant from most galactic trade centers, the moon was allowed to run its own affairs with little outside interference.
Sections of the urbanized moon's vertical city included the Duros Sector and the Corellian sector, which contained three bars popular with bounty hunters — The Burning Deck, The Slag Pit, and the Meltdown Café—as well as another corner tavern called the Orange Lady.
In 3,951 BBY, the moon was visited by the Jedi Exile in her search for Zez-Kai Ell, a Jedi Master who cast her out of the Jedi Order. After the Jedi Civil War ended, Nar Shaddaa became swarmed by thousands—if not millions—of refugees from destroyed worlds across the Galaxy, and still more ex-soldiers from both sides in the conflict choking up its spaces looking for work and / or new homes. Its refugee sector was one of the most crowded in the entire galaxy, and tightly controlled by the Exchange. The Exchange was exploiting the refugees to lure any remaining Jedi into their hands. The Exile attracted the Exchange's attention by persuading Saquesh, the "Overseer", to loosen his grip on the Refugee Sector, and rescuing locals from Exchange thugs. After she went to the Jekk'Jekk Tarr to meet with the Exchange member Visquis, G0-T0 intervened in Visquis' attempts to kill the Jedi and collected a misinterpreted "bounty". However, her companions rescued her and they succeeded in destroying G0-T0's yacht, the Visionary, destabilizing the Exchange and other criminal organizations throughout the entire sector for many years.
The Ebon Hawk on Nar Shaddaa.
During the Cold War, both Republic and the resurgent Sith Empire were vying for alliances with the Hutt Cartel.
Around 1,002 BBY, the Brotherhood of Darkness operated a Sith academy on the world that specialized in the training of Sith assassins. In 1,000 BBY, after the Ruusan campaign, Set Harth and Bal Serinus dueled on the moon, but were both imprisoned by a Hutt crimelord.
Before her death in 32 BBY at the hands of Darth Maul, native-born Pa'lowick Aneesa Dym and her ship the Dusty Duck called the Smugglers' Moon home.
In 28 BBY, the Colicoids took over the spice processing on Nar Shaddaa. Han Solo spent part of his early career as a smuggler on Nar Shaddaa. There, he learned the tricks of the smuggling trade from some of the galaxy's best smugglers such as Salla Zend, Shug Ninx and Roa. He had an apartment on the Smugglers' Moon, which was maintained by his old house-keeping droid ZeeZee, but after he decided to leave the moon for the Corporate Sector, it was left unused.