Bubblegum Alley
Though there are bubblegum walls in several locations across the US, the Bubblegum Alley in San Luis Obispo, California, stands 65 feet long and 15 feet high, and has been covered in chewing gum for years.
When the local business association attempted to have it cleaned in the 1990s, they were refused, and the alley was left in all its gum-filled glory.