This Josephine Baker enamel pin  has you swinging all summer long

In Napoleon's time it was imperative that soldiers had incisors in perfect condition in order to open their powder magazine with the teeth to recharge their rifles that they had to hold with their two hands. All those who had teeth apart were then classified as unfit to fight. Some men broke their own teeth to avoid going to war. 
Hence the expression "Dents du bonheur" ("lucky teeth").

Or one of the most beautiful cars ever made.