ACCESS THE TOMB
From the Temple of Kukulkan Base Camp, head left down the cliff to reach the tomb entrance. Head inside and dive under the water to follow the tunnel on the left. There are two air pockets along the way if you need them, but the path is straightforward.
Squeeze through the opening at the end and resurface. Climb the craggy wall to the top and pick up Relic – Primitive Doll on the right before you head up the slope. Jump to the ledge opposite and drop down to the ground. There’s a survival cache on the other side of the room – swim over to reach it.
Head right from the survival cache to climb up to the doorway above. Go through, inspect the mural on the right, then continue forward to reach the Subterranean River Base Camp.
REACH THE STELE
Jump down into the water below the Base Camp and swim forward to enter the cavern with the aqueduct. The stele sits in a room at the top of the aqueduct – to reach it, you must raise the water levels.
- Drop down to the bottom first to kick the raft into the middle of the room. Then tether the raft to a rope coil at the base of a gate on the left. Then climb back up and pull the mechanism against the wall to raise the water. As the raft rises, the gate opens.
Swim through the gate and follow the tunnel to reach a pry barrier. Break it open and squeeze through into the next room.
On the far wall there is a lever next to a gate. Interact with the lever to drain the water out of the room. Rope pull the barrier down on the left that blocks access to the first chamber. Take out the Yaaxil that appear.
Move the raft into the second chamber, then return to the mechanism to raise the water again. The raft should now float beneath an opening in the wall above. Climb onto the raft and through the opening.
Follow the corridor and pick up the ammo if you need it. In the next room, more Yaaxil appear – take them out. Climb up the far side of the room. At the top of the ramp are three more Yaaxil, so get rid of them, too.
Pull the mechanism on the left wall to raise the water again. As the raft drifts by, hop onto it to let it carry you around the central island. When you see the waterwheel, tether a rope between the raft and the coil on the far side. This will pull the raft close to the platform, so climb up.
Next, tether a rope between the waterwheel beam and the anchor hanging above that acts as a pulley system and raises the hanging block in the middle of the room. This causes Yaaxil to appear, so get rid of them.
Now tether a rope between the waterwheel and anchor again to raise the block, then use a rope arrow to pull the raft towards you. Jump onto the raft and then to the central island on your left once you’re close enough.
Make your way up until you can balance on the beam above, then jump to the stone block and over to the doorway on the opposite side.
Now you can interact with the stele to learn a new Skill!
EXIT THE TOMB
Follow the water channel on the right to find a zipline. Slide down it into the water below just beneath the Base Camp. From here, you can exit through the same path you entered. If you’re returning here at a later time, then simply fast travel out.