The Scottish racing driver Allan McNish, a two-time winner of the famous French endurance race, says all the technical preparation until race day doesn't prepare you for the "magic" of Le Mans.
In or out of the car, Le Mans is a day-long test of nerves
The 24 Hours of Le Mans is the original and ultimate endurance race.
As the clock reaches 3pm in France for the 79th running of the event at the Circuit de la Sarthe later today, each of the three-man teams will cover the equivalent distance of a Formula One driver over the entire 19-race schedule.
It is a similar distance to travelling from the centre of Abu Dhabi to Audi's headquarters in Germany, a place that Scottish driver Allan McNish has frequented for much of the race build-up as he finalises his bid for a third Le Mans success.
The former F1 driver won the prestigious event at his second attempt in 1998 for Porsche and again a decade later in 2008 for Audi, while also coming very close to wins on other occasions.
This year's Le Mans will be his 12th time on the grid and he describes it as an "event like no other"; unsurprising, as he will barely sleep for 24 hours and will drive for three-and-a-half hours at a time while his heart will be going at 140 beats per minute.
On his debut in 1997, McNish lasted just eight laps and, that year, he revealed he had never really felt the magic of Le Mans.
"I remember watching it back in the 1980s and, growing up in Scotland, there was definitely a feel for the history of the place," he said. "There was a Scottish team, Ecurie Ecosse, that won it twice, in 1956 and 1957, whom I came to know as they sponsored me in karting.
"But I was quite technical about the whole thing. For me, it was about getting a race drive there and competing. The magic hadn't set in but, from the moment I set foot there for the first time in 1997, I had a shiver down my spine and goose bumps.
"For the first time in my life, at the age of 27, I finally understood what Le Mans was all about. It's fine to read about it but, until you go there, stand there, feel the tension on the startline, take in the iconic pitlane buildings, listen to that deafening silence just before the race starts and hear the roar of the cars as the time reaches three o'clock, you just don't understand. It's magical."
McNish will once more team up with Tom Kristensen and Rinaldo Capello - the winning trio in 2008 - for today's spectacle.
Unlike F1, it is not just about being quick but ensuring the car stays together for 24 hours without sustaining any damage.
Each lap lasts about three-and-a-half minutes and takes in part of the Circuit de la Sarthe but also some of the surrounding public roads for an endurance test that is roughly six times longer than the historic Indy 500.
Once behind the controls for each of his stints, McNish said the adrenalin kicks in, but the nerves are always in abundance at the start.
"Whether you're in the car or watching your teammate at the start, there's more than a few butterflies," he admitted. "You can feel the tension and your heart pounding. You feel unbelievably nervous but that goes the minute the race begins.
"The thing is that this isn't just a race that you can have another go at next week or the week after. This is your entire season all into one race, admittedly a very long race. It's the thing that you've been thinking about and talking about since the previous November. It's your reference point for every test you do."
McNish said he tends to stay wide awake during the race. He will occasionally lie down in the motorhome but explained that, "you never really sleep, you shut your eyes but you just can't shut off with all the noise going on around you. Your mind's awake, alive and you just want to know what's going on".
Until the clock reaches 3pm tomorrow - crashes and mechanical issues permitting - and the chequered flag is waved, McNish will not allow himself to relax.
"You're on edge for the whole race," he explained, "particularly if you're leading and you don't relax for a second until the very last moment and the chequered flag is waving.
"Take the Indy 500 for example the other day. J R Hildebrand was leading until the very last moment of the very last lap and he crashed. That shows how cruel motorsport can be, so you have to keep focused until the last second.
"Then you cross the line and it's just an instant relief. If you're in the car, you're screaming and shouting. If you're not, you're hugging the rest of the team."
In 1998, McNish was at the controls as his team crossed the line while, 10 years later, he watched from the sidelines.
He relishes having been through both experiences but readily admits that one is considerably better than the other.
"Don't get me wrong, it's nice to have people to celebrate with when watching the race, but being outside the car watching those last few laps is just awful," he said. "You're just utterly helpless and that's not what you want as a driver."
Both times he has won, the celebrations have been short-lived. After team celebrations and press conferences, on both occasions when McNish has finally sat down, he has hit the wall.
"Each time, it's got to 8pm, just five hours after the race, the adrenalin has worn off and I'm like, 'that's it, I'm done'," he said. "I remember looking at Tom and Rinaldo in 2008 and all of us at the same time agreed we can't do anything else, it's time to go to bed. And then you just sleep a great sleep."
A good night's sleep has been harder to come by in the years when he felt he should have won.
In 2007, he looked on course for victory only for the team to pull out 262 laps into the race.
"It's awful when it happens like that as you go home and it haunts you," he added. "Suddenly, the race has slipped away and there's nothing you can do about it. You then just try and make yourself feel better by trying to win every other race that season."
Le Mans is also renowned for some spectacular crashes over the years. McNish has been lucky and come away relatively unscathed, bar one accident a few years ago.
"I came into the Porsche curves and the other Audi in front of me, driven by JJ Lehto, just blew up and I hit it at speed and just flipped," he recalled. "I woke up in hospital with a concussion and bruising and I wasn't allowed to drive for a month. So that certainly shook me up a bit."
However this year's race unfolds, it will always have a special place in McNish's heart. He credits it as the event that turned around his motor racing career but admits that his two wins are not necessarily the best of his time in motorsport.
"The 1998 win completely changed my career," he said. "I was a slightly forgotten man of motorsport at that time and then suddenly F1 began to call once again.
"But is it my best-ever win? It's probably right up there, but it's difficult to know whether it rivals my first-ever win in karting."
McNish will line up today to try to win the race for the third time. "For me, it's always been about the win. It's a special race, with special memories for so many different people. I hope to have a few more myself."