My favorite painting in the world is Jackson Pollock's Mural, his first major painting. It's owned by my alma mater the U of Iowa. The canvas is 9x20 iirc, just huge. They used to display it in a large central gallery, where you could look at it from more than 50 feet away, or get your nose right up to it.

One of the great things about this painting is how it is a totally different experience at different distances. From a distance, the sense of right-to-left motion is palpable. Get closer, and figures seem to pop out of it. But really close, you can no longer see the entire painting, but you can see individual brushstrokes (mostly 3-6" house painting brushes, I think). The subtlety and detail of each stroke is extraordinary. There are patterns across the canvas that are a result of large-scale patterns of strokes - it's almost like cursive handwriting.