Way back in 1968, Porsche built a test vehicle called the 909 Bergspyder. A single-seater built specifically to participate and win hillclimb races, it weighed a mere 847 pounds (for reference, today's Mazda MX-5 Miata weighs about 2,330 pounds). It was the lightest racing car ever put into use by Porsche. Jump ahead to 2015, Porsche assigned a new project to a group from Weissach to build a new seriously lightweight sports car based on the 981 (third) generation Boxster.

The goal: to be as light and minimalist as possible. In fact, the prototype was to be even more radical than the Boxster Spyder in terms of power-to-weight ratio. Superior driving dynamics were also a must. The one-off 909 was the inspiration and the result was the 981 Bergspyder which Porsche never revealed its existence until now. And like its ancestor, the exterior colors were easy to choose: white with green trim.

The 981 Bergspyder is a single-seater sans roof and windscreen, but it does have a flat, transparent wind deflector that extends around the driver and ends at the doors. Engineers and designers also created a cover to extend from the windscreen to the engine compartment – a direct homage to the 1954 356 Speedster. Although the new car's underpinnings were third-generation Boxster, the new 981 Bergspyder's dashboard was completely redesigned and received various elements from the 918 Spyder. Even the seats came directly from Porsche's then-new hybrid hypercar. Although the 981 looked like a one-seater, its passenger door could be opened to access a hidden compartment behind it fitted with a helmet shelf and a removable cover for the driver's seat and additional luggage.

Along with various weight-saving methods such as minimal insulation and carbon fiber interior components, power came courtesy by the 3.8-liter boxer engine with 388 hp from the Cayman GT4. Zero to 62 mph happens in just over four seconds and it achieved a Nurburgring lap time of around 7 minutes and thirty seconds.

So why didn't the 981 Bergspyder make production, even in limited numbers? Porsche was concerned whether it would be eligible for registration in most countries, obviously due to safety issues. The decision was ultimately made not to pursue production and the 981 Bergspyder remained a one-off prototype.

It was displayed for two years at the development center in Weissach before being reassigned to the Porsche Museum. And it will now be shown to the public for the first time during the 2019 Gaisberg hill climb race.