What's the Number One Game Other Than Blackjack?

In Russia, it's called Six-Star Poker, a variation of a career against the poker. In Southern South America, Roulette is really big, as well as Europe. And I've noticed that in Asia, Bocaras King, here it's Blackjack. So can you tell us more about other parts of the world that may have another game that's the number one gameother than those three?