From GTPlanet Game Guides

Eiger Nordwand

The Eiger Nordwand is a track featured in Gran Turismo HD and Gran Turismo 5: Prologue, although there is no real track by the same name, the game track is based on a road that is set on a high mountain pass below and between the Eiger and Lauberhorn peaks in the Bernese Oberland, Switzerland, named Kleine Scheidegg

The track in Gran Turismo 5: Prologue varies slightly, but noticeably, from the track in Gran Turismo HD, usually by the track being shorter, longer, wider or narrower in certain spots.