The Atacama Desert, Chile.
The driest non-polar desert on earth.
Average annual rainfall? Under a millimetre, with some regions waiting decades between sparse showers.
The temperature swings from 30C in the day to below freezing at night.
It is a region so barren and devoid of life that Nasa regularly uses it to simulate and practise for their landings on Mars.
It sounds like a tricky enough place to organise a Parkrun, so where do you even begin organising a 310-mile non-stop ultra-marathon?
If your name is Nils Arend – and your race is The Speed Project – the answer is simple.
You don’t.
It’s 4am in late November in the Chilean beach city of Iquique.
Ninety runners from all over the world are limbering up in a deserted skatepark on the beachfront, 50m from the Pacific Ocean.
The streets, other than a host of stray dogs, are deserted. Apart from the buzz of camera drones flying overhead and the nervous energy of the short-shorted runners milling about, it is strangely quiet.
Until a voice rises above the rest.
It’s the softly spoken German-American fusion accent of the man who has convinced everyone to be here.
And, more importantly, to leave here, on foot, and run across the Atacama Desert, alongside the main highway, to the ‘finish line’ at San Pedro de Atacama, some 500km away and at an altitude of 2,400m.
Like the American version of The Speed Project (TSP) from Los Angeles to Las Vegas which made organiser Arend’s name, this race has no prize money, no rules, no set route and no website.
And, like LA-LV, there is no official way to enter.
Invitations and intros come via Arend’s WhatsApp, and the event itself is unsanctioned and entirely unsupported.
Unsupported, perhaps, but certainly not under the radar.
Among the 90 runners – broken down into 15 teams of six – are former Olympians, a high-profile American TV presenter, the so-called “real-life Forrest Gump” William Goodge, who this summer became the fastest Briton to run across America,, external and former women’s international footballer Daniela Andrade, who has run the length of Chile solo.