Belgium's Spa-Francorchamps circuit is among the most historic on the Formula One calendar, having hosted a Grand Prix as long ago as 1924. Run on narrow public roads, the original Spa layout was a colossal 14.9 kilometres long and notoriously dangerous. Lap distance was reduced slightly over subsequent years and some corners eased, but when the 'old' layout staged its final Grand Prix in 1970 it still measured just over 14 kilometres.
Spa did not return to the calendar until 1983 and then in drastically revised form, with lap distance cut to just under seven kilometres. However, the circuit's magic was retained. Around two thirds of the lap used the original layout and the legendary Eau Rouge corner remained intact.
More than twenty years on, Spa remains the longest circuit on the Formula One calendar. Its mix of long straights and challenging fast corners, coupled with a picturesque setting, mean most drivers rank it amongst their favourite tracks. Integral to the challenge is the fearsome Eau Rouge which, with its high speed and sudden elevation change, maintains its reputation as one of the world's most technically demanding corners. The weather is notoriously changeable too, with the Ardennes micro-climate meaning it can often be simultaneously raining on one part of the track and dry on another.