'Le Mans is one of the most important races in the world. You can nearly cover the distance of an entire Formula One season on a single weekend with the same car without any technical modifications. It makes the race so special,' says Wolfgang Ullrich, head of Audi Motorsport.

Most car races run for less than an hour, sometimes only 15 to 30 minutes, and Formula One events that last for one to two hours are exhausting for the driver, machine and team. An endurance race is considered the ultimate test, as machines need to last the equivalent of lifetimes of use and abuse, and drivers need to work round the clock in shifts and teams. They have to be awake, alert and able for much more than the 24 hours of race time.

The first 24 Heures Du Mans was held in 1923 and went on to inspire the endurance event called the Le Mans Series, with many teams and drivers focusing specifically on this type of car race. 'There are anywhere between 5,000 and 10,000 parts that make up the racing car. So, mechanical reliability [and] mechanical excellence attract the major carmakers, attracts tyre manufacturers, and attracts component makers. You get such a conglomeration of specialists who are the best in the world, and I think there are a lot of lessons to be learned from it,' says three-time world Formula One champion Jackie Stewart.

Racing at Le Mans presents far different challenges from Formula One. For one thing, a good portion of the race is run in the dark. Driving into the rising or setting sun every few minutes also takes its toll. Long straights allow drivers to flex their fingers for a moment if no one is on their tail, or to speak with the crew just to help them stay alert.

Coming into the pits presents different challenges as well, such as pulling a body which is tense and tired out of a cramped cockpit. Even things such as bathroom breaks, food and hydration need a special time and place as they can't be ignored as in a much shorter event. The team and pit crew have similar issues, and walking through the pits and paddocks will see crewmen catching whatever break they can on bare floors or tyres.

In 2006, Audi was the first to win with a diesel-engine car, a technological tour de force that also became an important marketing statement.

Michelin radials were first run at Le Mans in 1951 and disc brakes in 1953. Halogen headlamps were tried in 1963, and Porsche experimented with turbochargers and longevity in 1974. All these and more had to be developed and tested to destruction on the track, and all became everyday products of modern life.

A walk through the camping grounds will often have you weaving between Rolls-Royces, Ferraris, Bentleys and badly pitched tents that the owners are trying to sleep in. Buses become temporary sleeping quarters, and larger tents are often used by the big companies to house media, the team and guests.

Drivers, crews and fans alike prepare for months, if not years, to experience those magical 24 hours. 'As the night racing is the most magical part of the whole Le Mans experience, I believe it is absolutely essential to experience every second of it,' Hounsome says. 'Not to do so is verging on sacrilege.'

This year's finish was the fourth-closest in history, and came after two horrendous crashes early on took out the two other Audis that were in contention. Marcel Fassler of the winning Audi R18 team became the first Swiss driver to take top spot on the podium, not without learning that time really does play tricks on even the best at Le Mans.

'The last six hours were incredible. It just seemed like they wouldn't pass. When I looked at the time I kept thinking it had stopped. I said to myself: the clock can't be running, it would have had to be over a long time ago,' Fassler says. 'You could see the dream coming closer and closer. And then there were moments when everything became increasingly difficult ... And then you start trembling again: Will the dream really come true. And then it did come true. It's really fantastic.'