What are Rolligon tires?

1957 Rolligon Transporter - Albee AutoWP.ru

They've been described as gigantic watermelons attached to otherwise unremarkable vehicles, and you can even watch these tires roll over a person without harming them. But what exactly are Rolligons? Whatever happened to them?

Topics in this Podcast: howstuffworks, ben bowlin, Scott C. Benjamin, U.S. Army