Associated Press -- Over the course of 80 years, the unusual "See Rock City" advertising campaign led to as many as 900 painted barn roofs at its peak with surprisingly effective results. But as Americans turned to interstates for travel and began bypassing back roads, the roadside attraction known as Rock City began maintaining fewer sign, leaving the paint on the remainder to fade and the barns to slowly rot.

By 1998, there were only about 200 See Rock City barns left, and that number has decreased to only about 100 today. Of those, only about 10 are left in Alabama.

Rock City, located in Chattanooga, was the brainstorm of Garnet Carter and his wife, Frieda. Carter was also the inventor of miniature golf - he created Tom Thumb courses that soon became a hit nationwide.

Rock City Gardens, which opened in 1932, featured panoramic views from atop Lookout Mountain as well as unusual rock formations. Frieda also added scenes and gnome-like figures to the gardens to create "fairylands" and other visual surprises.

In 1935, Carter had the idea to advertise on barn roofs along routes leading to the attraction, eventually advertising on barns from the Great Lakes to the Gulf of Mexico, according to SeeRockCity.com. He hoped the signs would lure Americans, who had just begun traveling again as the Great Depression ended, to his unique attraction. It worked.

Most of the barns were painted by Clark Byers of Chattanooga, who spent 30 years painting such slogans as "The Eighth Wonder of the World" and "When You See Rock City, You See the Best" on roofs in 19 states. He retired in 1969 and died in 2004. A few of the barns are still maintained by Rock City.

"Today, spotting one of these ever-recognizable structures not only gives tourists a look at a historic landmark, but takes them on a nostalgic jaunt back to a time when motorists drove blacktop lanes in search of family fun," the website says.