A mafia or a "gang"?...just thought of this..like NYC had mafias and california had and has gangs...which is more deadly and or more scary?? Me personally,I grew up 5 mins from queens ny,which is where a shit ton of gangsters hung out..I'm way more afraid of the mafia than some random black of hispanic guy in cali with a gun....bloods and crips are very dangerous but they can't touch the mafia!
The mafia is more organized & more ruthless. Even though they're not as relevant anymore. There were gangs in NY as far back as the mid 1800's (ex: The Four Points)
Both started like hundreds of years ago, but crime families were probably first. You can find them from the italians to the arabs.
Well I though it will be same question Until today in Japan, USA, China... there is still Yakuza, but they split to many parts like Gurentai.