There's definitely a mafia.
I lived in Italy for several years and, even as a clueless foreigner, some things were pretty obvious. For one, they have an entire branch of the police dedicated to combatting the mafia. Walking down the street and seeing a sprawling building called "Anti-Mafia Headquarters (in Italian, obviously)," is kind of a shock.
I also remember at one point (circa 2000-2001) there were a bunch of news reports about the mafia stealing massive quantities of water in the south and then selling it at a premium to the local farmers, who were already dealing with a drought (the crime was discovered when a pilot flying overhead spotted a couple of lakes where there shouldn't have been lakes). Seriously, stealing a lake? That's some super-villian shit right there.
The most direct evidence I saw of the Mafia though, was when I was traveling through Puglia (a region in southern Italy). I was enjoying the ride through olive orchards and vineyards when we passed one vineyard that looked like it had been hit by a tornado. All the little frame things were knocked over, and it was just generally trashed. My companion on that trip was a local and I asked him what had happened. I thought perhaps there had been a nasty storm and this vineyard was just the last one to repair the damage. His response? "The mafia."
If we had been in public, he probably would have waited to tell me until we were someplace private. Just talking about the mafia can get you in trouble.