[Paul Ross]

I don't think its that hard to visualize the collapsed caldera, as the walls do obviously trail inward, rather than out. But it's difficult to perceive from this angle that this caldera is elevated drastically above the surrounding planetary surface...actually sitting atop the tallest known volcano in the solar system. We need an angle shot, rather than one from directly overhead.

[cogitator]

But it's difficult to perceive from this angle that this caldera is elevated drastically above the surrounding planetary surface...actually sitting atop the tallest known volcano in the solar system. We need an angle shot, rather than one from directly overhead.

Or a simulation like this:

and adding a bit of vertical exaggeration:

(What did we ever do before Google Image Search?)