The circuit's conception emerged from a meeting at the Hotel des Bruyères in Francorchamps in the early 1920s. Jules de Thier, owner of the Liège newspaper La Meuse, gathered burgomaster Joseph de Crawhez and racing driver Henri Langlois van Ophem to assess a road route connecting Francorchamps to Malmedy and Stavelot. The triangle of public roads offered long fast sections with few tight corners, and the decision was made to use it as a racing venue.
The inaugural race was planned for August 1921 but cancelled when only one driver entered. The first car race was held in 1922, and 1924 saw the inaugural running of the 24 Hours of Francorchamps. Grand Prix racing arrived in 1925, marking the beginning of Spa-Francorchamps as an international venue. The Eau Rouge creek, which the circuit crossed near its lowest point, had historically formed the Belgian-German Empire border until 1920.
The original layout traced the public roads linking three Ardennes communities. From the start-finish area it descended into the Eau Rouge valley and climbed the Raidillon — an uphill sweeping corner introduced in 1939 that cut short a slower U-turn at the former customs post — before traversing the Kemmel curves toward the highest section of the track. From there it descended toward Les Combes and then through Burnenville into the village approach.
The Masta Straight followed: a long, near-flat blast interrupted only by the Masta Kink, a high-speed left-right chicane between farm buildings that became one of the most feared individual sections of any racing circuit. Speeds through Masta reached 298 km/h. After Masta, the circuit continued through the Hollowell Straight and a bypass of Stavelot into the fast Blanchimont left-hander before returning to the start-finish area. A full lap took between three and four minutes.
The track used ordinary public roads — houses, trees, electricity poles, and fields were positioned immediately adjacent to the racing surface. Before 1970, safety modifications were essentially nonexistent beyond straw bales. The conditions were described by former Formula One driver Jackie Oliver as a situation where, if you went off the road, you simply did not know what you would hit.
No section of the old Spa circuit acquired a darker reputation than the Masta Kink. Jackie Stewart, who had significant personal reasons to fear it, called it "by far the most difficult corner in the world." The corner required drivers to negotiate a high-speed left-right chicane at the end of a roughly 2.4 km straight, carrying speeds that made any error catastrophically consequential.
Stewart's assessment was formed by direct experience. During the 1966 Belgian Grand Prix his BRM ended upside down in a ditch near a Masta farmhouse, with fuel pouring over him, leaving him with broken ribs and a lasting determination to improve racing safety. His advocacy for safer circuits emerged in large part from this accident.
The Masta Kink was removed from the Formula One schedule after the 1970 season. It continued to feature in the 24 Hours of Spa touring car race until the old circuit's final years, and its presence in those events generated further incidents that contributed to the circuit's eventual decommissioning.
The 1960 Belgian Grand Prix saw two drivers, Chris Bristow and Alan Stacey, killed within 15 minutes of each other during the race. Stirling Moss was severely injured in practice. In 1969, Formula One drivers boycotted the Belgian Grand Prix entirely, citing the extreme danger of the circuit. The boycott succeeded in removing the race from the calendar for that year; Armco barriers were subsequently added and several sections improved before a return in 1970.
Even with improvements, the 1970 Belgian Grand Prix — which included a temporary chicane at Malmedy and still averaged over 240 km/h — was deemed insufficient by the drivers. The 1971 race was cancelled when the circuit failed to meet mandatory safety measures. Formula One did not return to Spa until 1983, on an entirely different circuit.
Multiple fatalities in the 1973 and 1975 24 Hours of Spa touring car races accelerated the old layout's end. By 1978, the event calendar had contracted to only the Belgian motorcycle Grand Prix and the 24-hour race; the World Sportscar Championship 1000 km race had ceased visiting after 1975.
Eighteen Formula One World Championship Grands Prix were held on the original triangle layout before F1 departed. The all-time lap record of the old circuit is 3 minutes 13.4 seconds, set by French driver Henri Pescarolo driving a Matra at the 1973 Spa 1000 km World Sportscar Championship race, representing an average speed of 262 km/h. The fastest single time ever set on the old layout was the pole position for the same race — 3 minutes 12.7 seconds by Jacky Ickx in a Ferrari 312PB.
In 1979 the circuit was fundamentally redesigned and shortened from 14.1 km to 6.947 km. The new permanent circuit retained the Raidillon de l'Eau Rouge, Blanchimont, and the La Source hairpin while eliminating Masta, Burnenville, and the village passages through Stavelot. The old triangle of public roads returned to civilian use; the majority of the route remains public road today. The start-finish straight of the old circuit was on the downhill approach before Eau Rouge — the opposite end of the track from where the modern circuit places its pit straight.
The original Spa-Francorchamps layout stands as the clearest historical example of the open-road racing tradition at its most extreme — simultaneously the fastest, most spectacular, and most hazardous circuit configuration that Formula One ever visited.