This is a very fun place to stop at if you're in Las Vegas. Not only do they have a history of M&M's but they also have a multi-level gift shop (Basically the whole thing is a multi-level gift shop) with every thing imaginable in M&M form.
There is also a part of the store which has M&M (plain and peanut) in every colour imaginable. THey're kind of expensive (up to $15/lb) but a very neat thing if you have someone who just LOVES purple and wants purple M&M's. Some people there were getting married and were getting colour-coordinated M&M's as party favours for their wedding. I thought that was neat.
THere is a history of M&M walking tour you can go through and at the end they give you a tiny bag of M&M's as a gift.
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