There is no shortage of classic cars from history, but the list of iconic autos that are still in production is relatively short. So why is it that some cars shine brightly and then fade, while others achieve a status so significant they never lose their luster? Undoubtedly, some cars are products of their time, but their allure eventually wanes; think Chrysler's PT Cruiser. Sometimes, nameplates are abandoned out of sheer embarrassment (Suzuki Samurai). But on rare occasions, a car manages to avoid the fickleness of fashion and the potholes of poor design to become timeless, living on generation after generation. Click through for a look at automotive immortals still treading American roads today.