"The Circuit de Spa-Francorchamps is the famous venue of the Formula One Belgian Grand Prix and the Spa 24 Hours endurance race. It is considered to be one of the most challenging race tracks in the world, mainly due to its fast, hilly and twisty nature. Spa is a favourite circuit of many racing drivers and fans. Over the years, the Spa course has been modified several times. The biggest change saw the circuit being shortened from 14 km (8.7 miles) to 7 km (4.35 miles) in 1979. "