In the Triassic, about 240 million years ago, on the bed of a shallow sea, dark grey, relatively hard layers of Alpine muschelkalk (shell-bearing limestone), so-called Wurstelkalk, were laid down in the area of the present day Partnach Gorge.
Importantly, about 5 million years later, softer marls were deposited in the same marine basin, which today are known as Partnach Strata (Partnach-schichten).
The erosion force of the Partnach stream, fed from the Schneeferner glacier on the Zugspitzplatt plateau, was great enough to carry away quickly the softer layers, to keep pace with the continued uplifting of the terrain and thus to cut into the hard Alpine muschelkalk as well.
The gorge was already being used by local peoples in the 18th century who, at risk of their lives, transported firewood from the Reintal valley on timber rafts to Partenkirchen.
Although the film's dialogue refers to the route as the Borgo Pass in the Carpathian Mountains (in accordance with Bram Stoker's novel, Dracula), the footage of the narrow passages and rushing water clearly identifies the location as the Partnach.