For my little boy's fourth birthday! He LOVES the Cars 2 movie, so I did this with the bottom tier as Mater, the middle as Lightning McQueen and the top as Professor Z (LOVED working on him!!). My Mater (Chocolate cake with chocolate chip cookie dough filling and dark ganache) completely melted in the sun, as you can see ... the ganache was liquid by the time we cut the cake, and the fondant had all slid off. Made for a great "after" picture too :). The other tiers (vanilla cake with coconut mousse filling, and peanut butter cake with honey filling) were covered in buttercream, and though they sweated and drooped, nothing slid down onto the next tier, thankfully, hehe. Thanks for your comments!