Jelly shoes were introduced to the United States at the 1982 World's Fair in Knoxville, Tenn., and the following year at a shoe expo in Chicago. It was at that February 1983 convention that the distinctive footwear really hit the map.

A Bloomingdale's purchasing rep saw the shoes at the Chicago expo and ordered 2,400 pairs. Those jellies sold both on the sales floor and in the store's catalogue.

Jelly shoes are often made out of PVC, or polyvinyl chloride, a commonly used material for a wide range of consumer products.

In 2007, close to 14.2 billion pounds (more than 6.4 billion kilograms) of PVC was consumed by the United States and Canada, in the form of hundreds of everyday products.

PVC is versatile and cheap to manufacture. Products made with PVC also tend to be low maintenance and long lasting.

Jellies are often made through the process of injection molding. PVC resin, along with other additive ingredients, is heated, forced into shoe-shaped molds and then allowed to set.

When it comes to jellies, there are hundreds of offerings under the sun, from all sorts of brands at various prices.

While some people think jelly shoes are perfectly comfortable, others beg to differ. They often cite biting straps and sweaty soles as the reasons they aren't fans.

Crocs are sometimes lumped in with jelly shoes, but not according to purists. The shoes are made with a patented synthetic resin, but it's not the traditional PVC so commonly used to make jellies. But using a loose definition, one could say Crocs can be grouped with jelly -- or plastic -- shoes.

Kids might have been the first to really jump on the jellies bandwagon, but adults took up the trend pretty quickly, too. Today, grown women, and to some extent, men, can buy jelly shoes as well. Some designer jellies are even pretty pricey -- up to $200 or more.