There are many different variants of slot machines, but it can be roughly grouped into two categories: classic slot machines and video slots. The classic slot machines are those that derive directly from the first 3-reel slot machine, and report on the wheels symbols like cherries, number 7, the word BAR, or even the famous Liberty Bell, symbol of the bell that has made one of first slot machine. Playing slot machines online is far much better than playing at land based casinos due to many reasons. The game of slots require not much skills but you must have luck playing at slot machines online.