One of the most famous explorers ever, Sir Edmund Hillary, has died at the age of 88.
Sir Edmund was the first person to climb Mount Everest, the tallest mountain in the world, on 29 May 1953.
Conquering the 8,850 metre (29,035ft) peak made Sir Edmund a national hero in New Zealand, where he was from.
The Prime Minister of the country said he was the best-known New Zealander to have ever lived, and the whole country would be sad about his death.
Sir Edmund was born in Auckland in 1919, and began climbing mountains when he was a teenager.
He attempted Everest as part of a group of climbers, but only two actually made it to the top - Sir Edmund and a Sherpa, or mountain guide, called Tenzing Norgay.
The two men only stayed on the summit for 15 minutes because they were low on oxygen.
Sir Edmund took photographs of the scenery and of Tenzing waving flags of Britain, Nepal, the UN and India.
After his Everest success, Sir Edmund led expeditions to the South Pole, and devoted his life to helping mountain guides called Sherpas in an area of Nepal called the Khumbu region.
His Himalayn Trust helped build hospitals, clinics, bridges, and nearly 30 schools.
Sir Edmund's health had been getting worse since April, when he suffered a fall during a visit to Nepal.