They do have altitude data. Hold control and drag the view, and you'll be able to explore it in 3D. As for why there's not much in the way of imagery, I'd guess

They do have altitude data. Hold control and drag the view, and you'll be able to explore it in 3D. As for why there's not much in the way of imagery, I'd guess it's because Olympus Mons is at least 40 million miles away at any given point.