Criptograma Chests are new to the Far Cry series and require you to find two Criptograma Charts to unlock them. These charts are hidden in the surrounding area, and you are given slight clues to where you can find them. Here is how you unlock the Higado Lake chest.
You will first need to make your way to Casa Marroquin. This small residence is located in the northern part of Sierra Perdida on the northern edge of the lake. Once you are here, find the house and climb up on the roof to locate the chest.
There is an arrow that points across the lake. Follow the arrow by heading southwest to a rundown shack. Be careful of any crocodiles that may be lurking around the area. Break down one of the doors to the shack, and the Criptograma Chart will be inside.
For the next chart, head southeast to a gazebo with crates of vegetables inside. The Criptograma Chart can be found in the gazebo attached to a smaller hut.
Once you have found both Criptograma Charts, head back to the chest to obtain your reward.
