3. Circuit de Spa-Francorchamps
A racing circuit set in Belgium and the home of the Formula One Belgium Grand Prix, the Spa 24 hours, and 1000km Spa endurance races, the circuit is regarded as one of the most challenging in the world. Originally built in the 1920’s, the race has seen a number of changes, including the alteration of the famous Masta Kink–a high speed left-right chicane in between two straightaways at which top speeds could approach 200 mph–in 1970. The Eau Rouge is one of the most famous portions of the track, at which point riders round a corner heading downhill and immediately shift into a steep uphill bank. Due to the physics of the turn, drivers can take the turn flat out due to high levels of down force, with Formula One racers taking the turn at over 300 km/h. Over 50 competitors and race track officials have been killed during races.