The bit of mars that fascinates me is the Hellis Planitia[1] A huge hole roughly opposite the globe from the large volcano complex[2] coincidence.. I think not.

I am vaguely surprised it was not higher rated for a rover mission. 7k meters down should do something interesting to the atmosphere if nothing else.

1. https://trek.nasa.gov/mars/#v=0.1&x=72.07800218650755&y=-42....

2. https://trek.nasa.gov/mars/#v=0.1&x=-116.4913302335018&y=16....

If there is life on Mars, it will be underground.

So if you can get 7km down without digging, that's the first place to look!