Princess Kate, 19, spent ten weeks on an international expedition to Raleigh in Patagonia, Chile, in 2001. Kate hiked in the wild and observed marine life.
2. Prince William was photographed in June 1999 after passing his first driving test in Cyrencester, Gloucestershire, when Prince William, 17, was delighted that his coach had brought him good news.
3. Actress and singer Catherine McPhee unveiled this incredible old photo of Megan Markle when the two starred together in a musical as teenagers.
Prince Harry, 4.18, took pictures in his dorm room during his final year at Eton College. Behind him are movie posters, stereos and a picture frame of Princess Diana.
5. Photo taken in 1942, 16-year-old Princess Elizabeth riding a bicycle around the Windsor Royal Lodge. Princess Elizabeth and her sister Princess Margaret remained in Windsor during World War II to escape German air raids.
6. In 2004, 16-year-old Princess Beatrice and 14-year-old Princess Eugenie visited a polo match together.
7. In 1962, 14-year-old Prince Charles wore a suit and smiled to take a picture.
8. In 1968, 18-year-old Princess Anne took a photo wearing a silk tunic and personality earrings.
9. Prince Andrew, 16, has just completed his first solo gliding flight and looks like he's doing well.
10. In 1978, the Queen's youngest son, the 14-year-old Prince Edward, looked childish during a visit to the Horse Racing Trials.
11. This rare photograph was taken in 1939, when Prince Philip was 18 years old and a student at The Scottish Goldston School.
12. Princess Anne's daughter Zara is a versatile equestrian who has loved sports since she was a child. In 1995, at the age of 14, Zara was photographed resting during a horse race at Gatcombe Park.
13. In 1991, Princess Anne's son, 13-year-old Peter Phillips, was photographed in Dorset.
14. In 1997, Prince Michael's 16-year-old daughter, Gabriela Windsor, took part in a military parade on the viewing platform at Buckingham Palace.