I actually collect M & M dispensers so M & M World was a must in Vegas. It is 4 floors. The 1st & 2nd floor can get very crowded. People actually knocked down and broke glass items when we were there because of the congestion. I went a second time at night and it was a much better experience. There are lots of M & M items: clothes, jewelry, mugs, dispensers, collectibles. You can take pictures with the M & M's (there was person dressed up as a yellow m&m outside & life size plastic ones upstairs). There is also over 20 different colors of M&M's you can get. This was a fun experience and worth visiting if you are any type of candy lover.