As a simple proof of concept we have put together a quick CryEngine based rendering of Stonehenge.
In the absence of any better data the terrain model is simple generic flattish land.
The model of the stones was beautifully crafted by Tom Harvey, using SketchUp and is available from the SketchUp 3D warehouse. A few edits in Blender and export to CryEngine's cgf format was all that it required. Scaling the model has proven somewhat problematic, and the results is based on what looks and feels about right.
The original textures, which don't conform to the CryEngine requirements, are also distorted, but overall the sense of place is interesting and we quite like running freely through the stones.