GTA Underground is a mod created for GTA San Andreas with the goal of merging all of the previous GTA maps into one mega environment. The mod even aimed to bring other cities from non-GTA games developed by Rockstar into San Andreas, including the cities featured in Bully and Manhunt.
The mod had already faced some problems from Take-Two in July. As result, it was removed from ModDB. It is now removed from all other official sources and sites.
In 2018, Kotaku interviewed dkluin about the mod and all the work going into it. He had started development on it back in 2014, when he was only 14 years old. GTA Underground isn’t a simple copy-and-paste job, instead, the modders added AI and traffic routines to every map, making them fully playable as GTA cities. The team also had plans to add more cities to the game, including their own custom creations.
Rockstar and Take-Two Interactive haven’t shared their official reasons for going after these fan-made mods, but many suspect it has to do with the upcoming GTA remasters. As reported by Kotaku last month, Rockstar is working on a collection that includes remastered versions of Grand Theft Auto III, Vice City, and San Andreas coming to the Switch and other platforms. Though the collection hasn’t been officially revealed, sources say it’s targeting a release later this year.