In an age with instant communication at your fingertips and digital marketing on every platform, there are those who still get out messages the old-fashioned way, with a paintbrush and some attitude. They call themselves “wall dogs,” says one veteran of the trade, “because we are chained to a wall all day by our safety harness, and we work like dogs.” Vocativ spent a day with these blue-collar artists as they paint advertisements high above the streets of New York City.