Trophy Description:Complete all optional tombs.
Gold trophy.

There are 7 optional tombs to complete. All of the tombs feature some kind of puzzle and are easy to complete. You might need an upgrade before you can enter the tombs though.

You will be notified when you are close to a tomb. You can also learn the skill Cartography to reveal the locations of all tombs and treasure maps.

PowerPyx has created an excellent video guide, showing each tomb's location and solutions of their puzzles.