When Prince Charles married Lady Diana Spencer at St Paul's Cathedral, the world thought they were watching the perfect love story.
The couple's beautiful royal wedding was watched by people around the globe, and everyone celebrated with them as they welcomed their two beautiful sons Princes William and Harry.
And while they looked completely in love as they smiled and waved for the cameras, things behind closed doors were very different.
The couple announced their separation in 1992 and finally divorced in 1996, with the Queen and Prince Philip saying they were "saddened" by the decision but "understood and sympathised".
However things started going wrong years before they agreed to go their separate ways, and royal experts believe there are several key moments which were the beginning of the end.
Dickie Arbiter, former royal press secretary, believes Diana and Charles's marriage started going wrong after William and Harry were born.
Speaking on the Channel 5 documentary Charles and Camilla: King and Queen in Waiting, he said: "Charles wasn't the fully hands on dad that she would have expected, and I suppose that created a distance between the two."
Vanity Fair's royal expert Katie Nicholl claims that Diana always knew Camilla was still on the scene, and it broke her heart.
She said: "She strongly suspected that Charles was still in love with Camilla and hadn't let go of her. Diana felt cut off, she felt isolated, she felt betrayed."
Another key moment in the breakdown of their marriage was during their Royal Tour of India in 1992.
Carole Malone, current affairs commentator, explains: "Diana had asked Charles to come with her to the Taj Mahal, the temple of love, and he refused.
"She was really hurt by that so she made a point of going on her own."
She posed for photos sitting on the bench outside the famous building, and told journalists she found the visit "healing".
When asked to explain what she meant, Diana simply replied: "Work it out for yourself."
After months of speculation about upset behind palace walls, the couple went to Korea in 1992 on what would be their final Royal Tour as a married couple.
Speaking on the documentary, Ingrid Seward, editor-in-chief of Majesty Magazine, said: "They went separately an they left separately I think the press really jumped on that and they realised this was going seriously wrong, but nobody apart from Diana and her intimate circle knew about Camilla at that time.
"That didn't come until later."
Charles and Camilla officially announced their separation shortly after arriving back in the UK, with a statement being read out in the Parliament, but they said had no plans to divorce.
