In Brazil| ""catadores"" collect junk and recyclables. But while they provide a vital service that benefits all| they are nearly invisible as they roam the streets. Enter graffiti artist Mundano| a TED Fellow. In a spirited talk| he describes his project ""Pimp My Carroça|"" which has transformed these heroic workers' carts into things of beauty and infused them with a sense of humor. It's a movement that is going global."