Explorer Sir Ranulph Fiennes has arrived at Everest base camp in his preparations to climb the world's highest mountain.
Sir Ranulph will climb the North Face of Mount Everest
Despite his background, the adventurer is not an experienced mountaineer and is scared of heights.
Speaking from 21,000 ft via video phone, Sir Ranulph told BBC Breakfast: "It is a good idea not to look down, except at your boots."
Sir Ranulph hopes to raise £2m for the British Heart Foundation charity.
He hopes to complete the expedition in the coming week.
"Behind me is a white wall of ice that is the approach to the summit of Everest. We hope to set out there in about two or three days time," he said.
Great Ormond Street
Sir Ranulph spent the past year preparing by scaling mountains around the globe.
The money he raises will help buy equipment for research into children with heart disease.
The funds will go to a specific unit in the Great Ormond Street Children's Hospital, focusing on the growing amount of heart disease in six and seven-year-olds.
Sir Ranulph had a heart attack in 2003 followed by bypass surgery, but months later broke records by completing seven marathons on seven continents in seven days.
"What we are doing is to ask the public to give donations to the British Heart Foundations," he said.
"The foundation is dependent on the public giving to it."