The 8.76-mile Spa-Francorchamps circuit was the quickest of all the classic road circuits and, many would say, the greatest. It swept on public roads through the mountains of the Ardennes in Southern Belgium and even in the dry was a character-building circuit.
In the wet it was only for heroes and since the region is known as 'The Pisspot of Europe' due to its weather, races have frequently been held in the wet. Spa itself is famous for its water and became a generic name for towns which promote their water for its alleged health-giving properties.
Spa was first used for racing in 1924 and the first Belgian GP was run in 1925 when it was won by Antonio Ascari, father of the Double World Champion, Alberto Ascari. It was then used frequently up to WW2 and became a fixture on the WC calendar from 1950.
Serious discontent with Spa began after a downpour in the 1966 race which caused several crashes, most significantly one involving Jackie Stewart which led to his campaign for improved circuit safety. There is no question that Spa was dangerous, but it was magnificent and a win there was a measure of the standard of a driver.
In 1969 the safety of the circuit was challenged by the Grand Prix Drivers' Association and the Belgian GP was not held that year. In 1970, a chicane was added to slow speeds (Pedro Rodriguez still won at 149.94 mph) but for 1972 the Belgian GP was moved to Nivelles.
The memory of Spa would not die, however, and in 1983 there was a new 4.31-mile circuit which incorporated elements of the original, but with an improved surface and run-off areas.
The start/finish line, which was originally on the downhill straight before Eau Rouge, was moved to the straight before the La Source hairpin in 1981. Like its predecessor the new layout still is a fast and hilly ride through the Ardennes where speeds in excess of 205 mph are reached.
The most famous part of the circuit, indeed, one of the most famous parts of any circuit, is Eau Rouge. Having negotiated the La Source hairpin, drivers race down a straight to the point where the track crosses the Eau Rouge stream for the first time, before being launched steeply uphill into a sweeping left-right-left collection of corners with a blind summit. The corner requires a large amount of skill from the driver to negotiate well and the long straight ahead often produces good overtaking opportunities for the best drivers at the following "Les Combes" corner.
"You come into the corner downhill, have a sudden change of direction at the bottom and then go very steep uphill," says Fernando Alonso of Eau Rouge. "From the cockpit, you cannot see the exit and as you come over the crest, you don't know where you will land. It is a crucial corner for the timed lap, and also in the race, because you have a long uphill straight afterwards where you can lose a lot of time if you make a mistake. But it is also an important corner for the driver's feeling. It makes a special impression every lap, because you also have a compression in your body as you go through the bottom of the corner. It is very strange... but good fun as well."
The 'new' Spa is the longest circuit on the F1 calendar and, many believe, the most challenging. It demonstrates the importance of driver skill more than any other in the world. This is largely due to the Eau Rouge and Blanchimont corners, both which need to be taken flat out to achieve a fast run onto the straights after them, which aids a driver in both a fast lap and in overtaking.
Since 2000, Spa has been a closed circuit and a new public road built to keep public traffic off the track.
Since inception, Spa has been famous for its unpredictable weather. Frequently drivers are confronted with one part of the course being clear and bright while another stretch is rainy and slippery. The numerous revisions to the layout have not changed one thing - Spa is still the 'Pisspot of Europe'.
Turn 1 (La Source) is frequently the scene of first lap fracas, before leading into the downhill section. Heavy braking down to 38 mph here.
Leading down Eau Rouge and into Raidillion creates extreme suspension compression as the relief changes from downhill to uphill. Good engine power is required for the uphill drag Turn 5 (Les Combes). Top speeds of 205 mph - one of the highest of the season - before braking down to 3rd gear and 85 mph for this right hander.
Turn 8 (Rivage) provides a challenge as it is a medium speed 180 degree corner, heading straight into Turn 9. Good balance and change of direction are required here.
Turn 10 (Pouhon) is a high speed left-hander, with entry taken at nearly 186 mph.
Turns 14 is taken at 85 mph before the cars accelerate through Curve Paul Frere which is taken at 60 mph faster than that before leading into the flat out turns 16 and 17 (Blanchimont).
With heavy braking into the Chicane after a prolonged high speed section, the brakes need to be ready instantly. Turn 18 provides a good overtaking opportunity.