Forza Motorsport 4's latest trailer explains how a real-world location was turned into the game's fictional Bernese Alps circuit.

A research trip to the Swiss mountain range resulted in photos and video footage of the region.

Those materials, combined with race course know-how and a fabricated history, resulted in the trailer's clips of a red Ferrari 458 Italia burning past towering crags.

Forza Motorsport 4 is headed for an Xbox 360 debut during the week of October 11 - a month after the multiplatform Driver: San Francisco and a month before Need for Speed: The Run.