"It seemed like a good idea at the time," laughs Nicolas, nervously, as he peers over the edge of the volcano, with his bicycle propped up against a huge rock of lava.
Six months ago Nicolas, a Reunion Islander, thought it would be a good idea to enter the Mega-Avalanche event - a 35km mountain bike race down the side of the volcano. It's billed as one of the most extreme sports events in the world. And now, on the morning of the big event, Nicolas is having a reality-check.
Normally, Nicolas, 32, is to be found running a grocery store in the island's capital, St Denis. Today, like Superman, he intends to burst out of a metaphorical phone-box and skid his way through the clouds, down near-vertical drops, through rainforest and sugar cane plantations - and all this while jostling with what he calls "499 other crazy dudes".
French dance music pumps out of a couple of parked cars. Some of these "dudes" are cheering and singing as they prepare their bikes for the descent. No wonder they are taking care of every nut and bolt. Some of their machines - and that's the only word to describe them - cost more than 7,000 euros. With their state-of-the art brakes and full suspension, they look more like motorbikes than traditional bicycles.
Mega-Avalanche has been an annual event on this lush volcanic island for fifteen years. Initially it only attracted a handful of entrants - mostly from Reunion itself. But recently Mega-Avalanche has become, well, mega - bringing top mountain bikers from across the world to take part in this incredible challenge.
On the starting line I meet Julien Absalon - the French Olympic champion. Even he is looking a little nervous as he repeatedly checks that his brakes are working - but not as nervous as Nicolas.
"I'm feeling good," he smiles. "My legs are good. The weather is good. I'm going to have some fun this morning."
"Fun" isn't the word most of us would use. This extraordinary challenge will require every bit of energy and power these guys have to muster.
"But for me, this is great training," says Absalon. "While it's freezing in Europe, I can come down here to the sunshine and compete in a world-class event."
Alongside Absalon on the starting-line is his brother, Remy, last year's Mega-Avalanche winner. He is much taller than than his gold-medallist brother, which, I suspect, makes Remy physically better-equipped for this race. The riders need immense power in their legs - to pedal through the tortuous uphill sections, but also huge upper-body strength, to keep the bike upright as it drills its way across the dust and mud.
As they wait for the starting gun, packed in like cattle, the sense of camaraderie is remarkable. There are about 30 world-class riders among the 500 competitors - but they chat and joke with the regular bikers, treating them as equals. Cycling down a volcano, it seems, is a great leveller.
Towards the rear of the pack are Tom Richards, 52, and his two twenty-something boys from Cambridgeshire in England. "Back home nobody really knows much about mountain biking," says Tom.
"In my village only a couple of other people care about it. Most people follow football and that's about it. But here we're among real friends, who share our passion."
Seconds later, the tape is suddenly lifted out of the way, and hundreds of bikers lunge forward together. It looks like the volcano is erupting all over again. A mass of flame-coloured Lycra flows down the track. Lava on wheels. Pushing their bikes to the limit. Putting their bodies through hell.
The dust is incredible. The clear mountain air turns brown in a couple of seconds. The dance music is momentarily drowned out by the clatter of wheels and the crunching of rock. A couple of bikers fall onto the ground, folding up their bodies and desperately hoping not to be crushed by the rolling stampede - like jockeys who've been thrown from their horses in the Grand National.
"Allez! Allez! Allez!" hollers the crowd. And then, silence. They have gone. The dance music pumps again.
But the craters in the ground and the huge chunks of volcanic rock are just the first challenge for the bikers. For the next 35 km they have to dodge all kinds of obstacles - while racing downhill at speeds of up to 60 kph.
The next challenge is sliding through the mist and mud of the rainforest. Visibility is restricted. Lethal tree roots stick out of the ground at all kinds of unexpected angles. Vines hang down from the trees - smacking the cyclists on their helmets as they career through the jungle.
There's no respite. A few kilometres further down the slopes, the cyclists emerge from the rainforest into acres of dry sugar plantations. Their sticky tyres - coated in rainforest mud - are suddenly covered in dry leaves as they crash through the countryside. The tranquility that most visitors cherish on this tropical island is momentarily destroyed.
Just 44 minutes after leaving the top of the volcano, Remy Absalon hurtles across the finishing line. It is a mind-blowing achievement. Thirty-five kilometres - through the most punishing of terrain - in less than three-quarters of an hour. His brother Julien finishes a few seconds later. And, then, over the next two hours the rest of the 500 bikers arrive.
Covered in dust and gasping for breath, the competitors remove their helmets, grab a coconut and collapse on the ground. Nobody seems to care who has won - not even the winners. Instead, the scratches on their faces and the blood on their arms, the bent handlebars and the buckled wheels are regarded as the real medals of honour.
"Yeeeeah!" screams Nicolas, as I see his forlorn-looking bike creaking across the line. He has a huge smile on his face - and an amazing story to tell his family for decades to come.