In 1942, in the middle of nowhere, an Army engineer posted the sign "Danville, Illinois, 2835 miles" to mark his hometown while building the Alaska Highway. That started the tradition of adding one's hometown signs to the heap. Now, there are close to 50,000 65,000 signs in what became known as The Sign Post Forest.

http://www.gosleepgo.com/guide/ca/yt/watson-lake/sign-post-forest | Flickr photos of the Sign Post Forest - Thanks JR!