Kuwaq Yaku – First Treasure Chest Near Village

After obtaining the LOCK PICK, later in the game, fast travel back to the Kuwaq Yaku or Jungle Cliffs Base Camp. Swim across to the east side of the river and around to the right (northwest) side of the first monolith.

Face the stairs leading down to the water and swim down to the wooden barrier below the surface.

This is the spot on the map.

Pry away the wooden barrier with your axe and swim into the cave.

Swim close to the treasure chest (1/2)...

...and hold Interact to open it with the LOCK PICK. Inside is an Artifact, Copal, from the Story A Community in Need. Apparently it smells wonderful, though I'm not sure how Lara can tell underwater. This item does not count as a relic toward the total for this level, but you can examine it later in the Artifacts menu. You also receive a few random rare resources.