I assume Elon is already working on his volcano lair under Olympus Mons... Assuming he's not I am guessing it would be easier to find a cave or Lava Tube (does

I assume Elon is already working on his volcano lair under Olympus Mons... Assuming he's not I am guessing it would be easier to find a cave or Lava Tube (does Mars have them?) than building something from scratch