It was at the 1973 Frankfurt auto show that Porsche first showed a prototype of a turbocharged 911 that would go on to spawn the original 911 Turbo just one year later.

However, what many may not know is that 1974 wasn’t the first year for 911 Turbo production because an example had already been built and presented to Louise Piëch on her birthday in 1973. Thus, Piëch’s 911 Turbo is officially the first example, and it now sits in the Porsche Museum in Stuttgart, Germany.

Louise Piëch is the mother of current Volkswagen Group Chairman Ferdinand Piëch and daughter of Porsche founder Ferdinand Porsche.

The video below, the latest from Porsche’s 911 Secrets collection, reveals that the first 911 Turbo was the private car of Louise Piëch so it has some personal touches: Piëch preferred that the car didn’t feature a Turbo badge and its windows be devoid of any tint. The latter was due to her liking to paint while sitting in the car, and wanting an unaltered view of the surroundings.

There had been considerable internal debate at Porsche at the time of the 911 Turbo's launch as to what sort of car this new 'super 911' should be. Some felt it should be a road-racer in the mold of the RS models, but others insisted the character of the Turbo—smooth, relentless, enormous power—lent itself to a true high-performance GT with every creature comfort Porsche could conjure, and at a premium price tag.

This template has been followed for every generation of the 911 Turbo since, including for the latest 2014 Porsche 911 Turbo.