Photo by JasonLiebig He has an awesome collection of old wrappers on Flickr.
Behold, the Marathon bar!!! This bar was a favorite of Robin Hood and King Arthur, it is, A LEGEND. Okay, that's not really true, but the way some people talk about the Marathon bar, you would think this was the greatest candy bar ever made. A legend, eaten by legends, and it included a ruler??!!
The Marathon bar was introduced by M&M Mars (Mars Inc.) in 1973 (wikipedia says August 1973 to be exact). The bar was eight inches long. The package had a ruler printed on it so you knew exactly how long it was. You can read Candy Blog's other explanation for the ruler HERE. The bar was a perfectly braided caramel that was covered in milk chocolate. Ounce for ounce it wasn't any bigger than today's candy bars but the novelty was the length of this candy bar (it was quite thin). This bar was pulled from the shelves in 1981 after a sales slump. Most people contribute the sales slump to Mars pulling a very successful advertising campaign in the late 1970s (see video below). I find it ironic that a bar with the slogan "Lasts a Good Long Time" was pulled from the market after a short 7-8 year run.
The Marathon name lived on in the U.K. on a bar that we'd call a Snickers bar in the U.S. Mars then pulled the Marathon name from the U.K. bars in 1990 and renamed them Snickers, so the Marathon legend is gone forever. If you are looking for a Marathon bar substitute, many people say the Cadbury Curly Wurly is a perfect fit. I've never tried one, so I cannot tell you for sure. Old Time Candy has a nice write-up on the Marathon and an ordering page for the Curly Wurly HERE. (BTW, I'm not affiliated with Old Time Candy in any way.)