Collect the indicated number of artifacts to unlock the corresponding concept art.

Art	How to unlock
Allies	12 Artifacts.
Co-op Levels	8 Artifacts.
Cutting Room Floor	36 Artifacts.
Enemies	22 Artifacts.
Extras	20 Artifacts.
Istanbul	28 Artifacts.
Nepal	26 Artifacts.
Odin And Seabed	32 Artifacts.
Panama	18 Artifacts.
San Francisco	14 Artifacts.
Sudan	2 Artifacts.