A high-drama helicopter rescue marked the end of a fundraising adventure by the son of British billionaire adventurer Sir Richard Branson on Wednesday.
Sam Branson, son of the Virgin Airlines founder, set off three months ago to raise money for Big Change, the charity he co-founded.
On CNBC's "Halftime Report," Richard Branson said that his son ran three marathons, rowed across the English Channel, cycled to Vervier and then climbed the 14,692-foot-high Matterhorn as part of the Virgin Strive Challenge. The Matterhorn is the most recognizable and dramatic mountain in the Swiss Alps.
"Today, three of them did manage to get to the top of the Matterhorn, and sadly my son, who did get to the top, suffered extreme altitude sickness, but made it and had to be helicoptered off," the elder Branson said.
"But he managed to get from the U.K. to the top of the Matterhorn, and they raised tons of money for young people in the U.K. who had issues, and completed a great mission."
Branson, himself known for such feats as attempting a round-the-world balloon flight, said that his son was all right.
"It's quite strange now seeing my son off rather than him seeing me off," he said. "He's fine. Everybody's fine. The Matterhorn can be a lot crueler than this."
—By CNBC's Bruno J. Navarro. Follow him on Twitter @Bruno_J_Navarro.