Book of the Dead is a demo of Unity's realtime graphics capabilities.

This blog post by CG and VFX artist Zdravko Pavlov goes into some of the techniques used to create its breathtaking photorealistic assets and VFX. Focusing primarily on workflows to create high-fidelity environment assets from still photographs, the article gives great insight into how photogammetry can be used in a game asset pipeline.

Even if it's not immediately useful due to lack of experience or equipment, definitely give it a read to learn more about modern asset creation techniques!