Whether you know it or not, you've seen a lot of work by Sky High Murals (Colossal Media). Based in Brooklyn, they are the largest hand painted mural and advertising company in the United States. With "165 years of cumulative sign painting experience," anything you can think of, they can do and probably already have. The Sky High Murals Tumblr features a collection of photos taken by the company of their handywork on walls, ceilings, and other surfaces large and small. Once you notice the "Colossal" badge in the photos, you will begin to notice it on walls all over New York City.