Next move to the middle of the three massive doors. The crystal globe here is
broken, so you have to USE the boom box in Play mode, which will produce the
sound you need to open the door. This is not a maze, thankfully. All you need
to do is go through the doorway over on the right Inside you will see a close
relative of the statue in Mexico, holding an ankh. PICK UP the ankh.
  Finally, you can open the massive door on the far right by either method, and
once you enter and go through the door in that chamber, you will find a force
field, which you turn off when you USE the ankh in the panel. PUSH the button
on the strange machine and you will see what I assume is a hologram of the
ancient aliens who prepared all this for you. PICK UP the smaller key on the
wall (the larger one will crumble into dust). At this point, it's time to leave
Mars, and go back to Zak.
  Save the game here, just in case you make a mistake. USE the yellow crayon on
the strange markings. By placing the cursor on the screen where you want to
draw a line, you can recreate the drawing the co-eds found on the huge statue.
When it's done, click on FINISHED DRAWING. The statue will release the crystal
shard and you can take it. Find your way out of the pyramid, return to the
airport, and from there to San Francisco. It's time to pick up Annie and finish
this game!