Shadow of the Tomb Raider

This achievement will unlock once you have successfully raided the sarcophagus at the end of three different Crypts. 

There are two Crypts in the Peruvian Jungle, another two in Kuwaq Yaku (one of which requires a shotgun), five in Paititi (two of which will require you to start the "Hearts and Minds" side mission), and one more in the Mission of San Juan. Some of their locations can be added directly to the world map if you speak with certain NPCs in these regions.

The main goal in each of the Crypts involves passing through its booby-trapped chambers, solving a variety of puzzles, and finding the sarcophagus. When you interact with the sarcophagus, you will be rewarded with a piece of a vestige outfit.