OK, Nick!
Maybe those three "small" dark dots in the infrared images of the farside wall
of Endurance Crater may not be caves, depending on your definition of caves.
Cubbyholes, maybe? Giant VUGS? Possibly just cracks?

Turning to the "assumed" cavern that may or may not exist on the otherside
of the Columbia Hills, I will stick my nose out and say it is a cave! Any WAGER
against me, my dear Aussie friend?

How would a cave be formed in those hills, you may ask?
Well...We surely agree to a volcanic and tectonic folding/uplift origin for
the hills....But what about the steep cliffs evident in the 3-D images?
Couldn't "sapping" beneath the rock overhangs involving trapped volcanic gases,
or percolating H2S04 [notice I'm not invoking H20] have created caves, or a cavern of sorts?

Jacob