The royal family's photographer shares his favorite photos of Prince William and Kate Middleton

The royal couple, who met as students at the University of St Andrews more than 20 years ago, celebrate their 11th wedding anniversary on April 29. Jackson took this photo of them in March 2017 as they toured the museum in Paris.

"I was looking around, looking at what might make a picture and what might not, and this seemed like quite a complicated silhouette, so I wasn't sure it was going to work," Jackson told Insider. "But I love this particular moment, where the duchess is between the spokes of the clock, and she's glancing out to the left slightly. It's just a little bit more unusual. It stands out from the day-to-day royal engagements."

"Pakistan is one of my favorite countries I've ever been to for royal tours," Jackson said. "It's got incredible color, energy. Everyone I've met has been very friendly."

Jackson snapped this photo as Prince William and Middleton were finishing their tour of the historic site.

"It was the last engagement of the day, and the light was stunning," he said. "I really enjoyed this moment as they were leaving the mosque."

Held at Alexandra Palace in London, the Earthshot Prize awards honor environmental problem-solvers with a total of $5 million for their sustainable solutions. National Geographic dubbed it "the most prestigious environmental award in history."

"It was a real buzz to be behind the scenes and capturing some of those special moments," Jackson said. "This is just one particular moment which I loved in the evening. Visually, I think it worked, and it was quite special to be doing that."

The photo featured Prince Charles and Camilla, as well as William, Middleton, their three children, Prince Harry, and Meghan Markle.

"I was very lucky to do a project with the Prince of Wales for his 70th birthday," Jackson said. "I photographed a lot of the prince behind the scenes in his 70th birthday year, and it culminated in this family portrait in the gardens of Clarence House, which was really an honor to take. I love this particular moment where the family are clearly enjoying themselves and it's just a lovely, relaxed moment."

"It was obviously this incredible moment and really highlights what is so special about being a royal photographer — to have a front-row seat to these particular historic moments," he said.

He added, "And this was watched by over 2 billion people around the world, the moment as the Duke and Duchess of Cambridge emerged onto the steps of Westminster Abbey on their wedding day and stepped into the light, I suppose, symbolic of embarking on a future together."