Though we'd refresh our case study of the Virtual Skiddaw project we did for the Open University a while back. The simulation modelled 100 sqm km (!) of the UK Lake District with 6 sites modelled at about ~1cm accuracy with photogrammetry. Students can pick up hand samples, look at virtual microscope slides, fly (!) around the environment and even lift up a cross-section of the rock!
The case study is downloadable here.
There are also a couple of great videos - a narrated walkthrough by the OU's geology lead on the project.
And the OU's Geology and vLearning leads discussing the project.
The app is still in use with students at the OU.