It's a hot, sunny day in June on the beautiful Mediterranean island of Sicily, but the problem is that I'm not on the beach, I'm running up a volcano.
An even bigger problem is that I've been going for two hours, but I'm only half way to the top and I'm tired.
This is Mount Etna, at 3,330 meters (10,926 feet) the highest volcano in mainland Europe and one of the most active in the world, and on Saturday I was one of 160 starters gathered on the beach for the "Etna Supermarathon."
The 43 km (27 miles) race is just a tad over the official marathon distance of 42.2 km. But much more significant is that it rises 3,000 meters from sea level, which the organisers say makes it the race with the biggest altitude change in the world.
It may be less gruelling than renowned "ultramarathons" like the six-day, 251 km Marathon des Sables in the Sahara desert, or the 246 km Greek "Spartathlon" from Athens to Sparta, but with the road getting steeper and the sun beating down it is feeling more than tough enough for me.
A twice winner of the Spartathlon was among the starters on Saturday, destined to finish in fourth place.
I have been running since I was a teenager, mostly road races from 5 km to marathons, but at 52 my aching limbs and waning performances have whispered to me for a while to hang up the racing flats in favour of more gentle jogs in the park.
But wouldn't it be nice to finish with something memorable and a bit "different," I thought.
Well this was certainly feeling different. The convivial crowd cracking nervous jokes on the beach as we looked up at the vast hulk of Etna and thought "can I really get up that?" is now a winding chain of silent runners, bent against the hills.
Like most marathon runners I am used to regularly checking my watch, but here the pace depends only on the varying steepness of the climb, so I forget the watch and try to focus only on catching some of the rash fast starters ahead of me.
At about 25 km I am happy to see my wife and son in the car on a lay-by ahead. They inform me I am in 13th place as they hand me a bottle of water and some cheers of encouragement.
We are around 1,400 meters up now and landscape has changed from verdant lemon groves, vineyards and villages, to oak and pine forests. The views over the sea are stunning, the air has become cooler but the sun is still too hot.
I slog on and spot more runners in the distance. The trees get sparser and the road is sprinkled with black, powdery lava. I keep hauling people in and morale is high despite the fatigue. But just before 33 km the slope gets sharply steeper and for the first time walking becomes a real temptation.
Then the road suddenly ends in a massive clearing surrounded by banks of lava and flattened trees that were floored by big eruptions in the spring. Someone shouts that I am in seventh place and a new, much tougher race begins.
I veer off onto a gravelly lava path, leave the last trees behind and all around me is a black, lunar landscape and impossibly steep gradients. There are only 10 km, but 1,200 meters of ascent, left to go.
I try to keep running but am often just wasting energy as the ground crumbles underfoot. There is thick snow mixed with the lava and the air feels thinner. I am now walking as much as running but to my relief no one is catching me up from behind.
Eventually I see a female figure far ahead, walking, and realise that she is the first woman. Then I glimpse the red arch of the finishing line what seems almost vertically above me.
I overtake the woman with about 800 meters to go and finish in 4 hours and 44 minutes in sixth place, almost an hour behind the winner but very happy, and looking forward to replenishing my energy with some of those amazing Sicilian cakes.
Gavin Jones (Reuters)