Circuit de Spa-Francorchamps

Designed in 1920 by Jules de Their and Henri Langlois Van Ophem, the original triangle-shaped course used public roads between the Belgian towns of Spa, Malmedy, and Stavelot. The track was intended to have hosted its inaugural race in August 1921, however this event had to be cancelled as there was only one entrant. The first car race was held at the circuit in 1922, and two years later saw the first running of the now famous 24 Hours of Francorchamps race. The circuit was first used for Grand Prix motor racing in 1925.

The old Spa circuit was essentially a speed course with drivers managing much higher average speeds than on other race tracks, a factor that made Spa very popular from its inception. Back then, the Belgians took pride in having a very fast circuit, and to improve average speeds, the former slow uphill U-turn at the bottom of the ''Eau Rouge'' creek valley, called the ''Ancienne Douane'' (until 1920, there was a German Empire customs office here) was cut short with a faster sweep straight up the hill, called the ''Raidillon''. Until 2000 it was possible to travel over the race track when it was still a public road. At Eau Rouge, southbound traffic was allowed to use the famous uphill corner, while the opposite downhill traffic had to use the old road and U-turn behind the grand stands, rejoining the race track at the bottom of Eau Rouge.

Source: Wikipedia