Sir Richard Branson came “seconds from death” as rocks “the size of fridges” rained down on him while climbing to the summit of Mont Blanc.
Branson was climbing with son Sam when “boulders the size of small cars” fell on the group.
The billionaire businessman said he was “lucky to be alive” after diving behind a small boulder with his son and other members of his team as rocks rained down from the side of a cliff.
He said: “We are lucky to be alive. Three seconds earlier we would all certainly have been killed.
“Throughout all of our challenges I have never come so terrifyingly close to losing myself, my son and other team mates and it all happened in a matter of seconds.”
Branson's brush with death occurred at the end of the first day of climbing as the 13-strong team made their way over the Gouter Couloir crossing – known as the 'Gully of Death'.
The Virgin Group founder was in the final group to traverse the crossing, along with his son and four others.
He said: “Within seconds of getting across we heard the most horrible sound. A side of a cliff had broken away from the mountain further up and seconds later huge boulders the size of small cars were bouncing towards us.
"Rocks rained down on us from every angle.
“I am not exaggerating when I say four of our team were seconds away from certain death.”
The 68-year-old eventually reached the summit on Saturday afternoon, completing the final of the 33-day Virgin Strive Challenge – a 2,000km trek across Western Europe, raising more than £1m.