The creation of Dolly the sheep in 1996 was undoubtedly one of the greatest scientific achievements of the 20th Century.
Its creator, Professor Ian Wilmut, has passed away at the age of 79.
Cloning was not his only great achievement. Wilmut laid the foundations for stem cell research - which scientists now use to treat many diseases.
Sheep cloning sparked much discussion at the time along with the fear of human cloning.
US President Bill Clinton even announced that he was stopping this research because it could lead to human cloning.
Professor Sir lan Wilmut's legacy is the creation of a field known as Regenerative Medicine, which has great potential to enable more people to live longer and healthier lives.
