Walk around New York City, and you're bound to see the work of these "wall dogs"—the men and women who paint billboard-size ads by hand, high above the city streets. Their work is exacting, and the places they paint are terrifying. Don't watch this if you're afraid of heights.

Hand-painted outdoor ads aren't exclusive to New York City. But the dizzying heights seen here definitely drive home the point that this isn't a job for the easily spooked. And in a city where artificial light and screens large and small dominate the view, there's something charmingly tangible about the craft and permanence of a hand-painted ad. At least until it gets painted over with the next big thing. [Vocativ via Digg]