Avi A. Katz is an illustrator who likes complicated scenes. "The messier a scene is, the more I’m compelled to draw it." he says. Cities, urban landscapes and architecture are his favorite sketching subjects. And he always makes sure there's an animal or two hidden in his illustration.
His sketches are detailed and conveys a good sense of space. There's also a bit of comic style from the digital colouring.
You can follow his sketches on Flickr.
If you like this style of art, check out Paul Madonna as well.