GR20: The “Hardest Trail in Europe” Falls in 27 Hours 29 Minutes

01A route from the 1970s

It all starts with one man: Michel Fabrikant. He had “just described an alpine route allowing the island to be crossed from north to south,” two geographers wrote in the journal Méditerranée in 1991. The Trailblazer guide presents him as an alpinist. According to the same study, the route was approved in 1971. The chronology of the Regional Natural Park of Corsica places the building of the first hut, Petra Piana, in 1971, and the assignment of the number 20 in 1972, the year the Park was created.

Why "20"? According to Finishers, it was the old number of the Corsica département. The route follows the watershed for much of its length.

02From Calenzana to Conca

From the northwest to the southeast, from Calenzana to Conca, with Vizzavona halfway, at the end of the northern part. Sixteen stages for walkers. On distance, nobody agrees: from 160 to 180 km depending on the source. On elevation gain, it is closer to 12,000 m.

03The "hardest trail in Europe"

The phrase is everywhere. The Regional Natural Park of Corsica itself calls it “one of the most difficult trails in Europe.” Finishers writes “Europe's toughest GR,” and the American site iRunFar calls it “Europe's toughest long-distance trail.” Who coined the phrase, and when? We found no origin. It is a reputation, not a measurement.

A leading guidebook adds nuance: for Trailblazer, the severity of the GR20 “definitely tends to be exaggerated.” But the first three days “claim a drop-out rate rivalling that of the French Foreign Legion,” and “barely half” of walkers complete all 16 stages, according to the same guide.

04The clock keeps shrinking

Runners have been taking it on for a long time. In 2009, Kilian Jornet finishes in 32:54. In 2016, François D'Haene brings it down to 31:06. In 2021, the Corsican Lambert Santelli runs 30:25. In July 2026, D'Haene takes the record back in 29:46, the first to go under 30 hours, ten years after his first record.

Two and a half months later, it is all swept away. Aurélien Dunand-Pallaz sets off from Calenzana on Thursday, September 24, at 5 a.m. and crosses the line at Conca on Friday at 8:29 a.m.: 27:29. “I took the risk of starting fast on the northern section, which is the most technical, despite the warnings,” he tells Corse Net Infos. At Vizzavona, he is 1 hour 40 minutes up on D'Haene's time. From Jornet's time to his, that is more than five hours gained in seventeen years.

One important caveat: these records are “supported.” Dunand-Pallaz ran with pacers who took turns, with organized aid, according to Reference Trail. On the women's side, the benchmark is Anne-Lise Rousset's 35:50, in June 2022.