"And a lot of them I haven't seen hung properly or hung at all. And so walking through, it's been hung so beautifully and the different sections and wall colours. I couldn't be happier. I'm just astonished by what we've collected and so proud of what we've collected because we both love photography so much."

Sir Elton said that there was also "a lot of pain and grief" on the walls, including images from the events of 11 September 2001.

"This is the first time I've ever shown our 9/11 photographs," he said. "Every time we get them out we think, is it going to be OK to show them, is it too raw?"

Of the 2,000 images of 9/11 they own, they are exhibiting just four. Sir Elton insisted it was important to collect images of that pain.

"The image of the man falling vertically from the World Trade Centre is one of the most beautiful images I've ever seen and yet it's one of the most tragic," he said.

"And sometimes in tragic images, whether it's paintings or photographs, there's a lot of beauty. And that's why the show's called Fragile Beauty, because there's beauty in everything."

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