If there is such a thing as the mafia in post-Soviet Russia—the Kremlin playing its own role as Godfather—it got its organizational start here. Solntsevo, a neighborhood in northwest Moscow, gives its name to one of the most dangerous criminal outfits in the world. Formed in the dying days of Communist power, the Solntsevskaya Brotherhood has ballooned into a powerful clan involved in arms trafficking, money laundering, prostitution, high-level fraud, and legitimate business. Hanging out in Moscow with these sorts of people has its thrills, but beware the price of adventure.