Rare, unseen Princess Diana photos The date: July 29, 1981. The place: St. Paul’s Cathedral. The stars of the show: Diana and Charles, the...

Rare, unseen Princess Diana photos

The date: July 29, 1981. The place: St. Paul’s Cathedral. The stars of the show: Diana and Charles, the newlywed Princess and Prince of Wales. Their prospects: According to the rapt world audience, sensational. Privately, dicey. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: Sygma/Corbis)

The cover of the new LIFE book “Diana at 50.” (Photo credit: Terence Donovan Archive)

Diana with her guinea pig, Peanuts, in 1972. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: UPPA/Zuma)

In February 1996, embracing a young cancer victim in Lahore, Pakistan. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: John Pryke/Reuters)

Charles and Diana with Prince William in Kensington Palace in 1982. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: Rex USA/Everett)

Diana with Prince William in Kensington Palace in 1982. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: Tim Graham/Getty)

On his first day of school at Wetherby boys school in Notting Hill, west London, Prince Harry looks up to his big brother, Wills, who will set an academic pace too fast to be equaled. This photo is featured in the new LIFE book “Diana at 50.” (Photo credit: Tim Graham/Getty)

A previously unseen photograph of Princess Diana and her sons taken by society photographer Lord Snowdon made a surprise appearance on the BBC's Antiques Roadshow on Apr. 2. Here are a few others dug up from our treasure vaults.