Southern Mexico - Xibalba
Tomb Raider Underworld - Visual Walkthrough
Jump and grab the upper ledge, move to the left and drop down (use E to prevent Lara from falling).
Grab the skull and get ready to get out of that hole (there's also an artifact nearby).
Here's how to get the artifact .. (if you just want to get out, DON'T go this way).
Ok, now time to get out of here. Use the small broken pillar to reach the nearby ledge.
Get out of the damn room and get back on the bike.
Get to the last temple thing.
Position the stone so that you can reach the hole and insert the pole on the ground in it.
Move the stone a bit further and jump on the pole. Wait until it is fully down then QUICKLY press Ctrl, drop down and run (use Shift) to the open door and roll under it (press Ctrl while running).
Put the item you got from the last temple in the hole on the ground and you can now move the rings and do the same you did with the first time.
The second part of the stadium will move and the entrance to the underground road will open. Be aware that you NEED to get to it fast since this part is TIMED. If you don't get it the first time, you need to return to the first wheels, do the quest again and .. try again.
Once you get it right you'll be in the underground and a cutscene will follow.
Go through the corridor on the left (on the bike).
Another artifact is around if you want to pick it up.
Be sure your bike has enough speed to jump over the gaps. Once you get to one you can't run over get off the bike.
Now you can jump over the gap and get to the next part of this level ...