Rediscovering Paul McCartney's photos of The Beatles' 1964 invasion

Paul McCartney used his Pentax camera the same way he used his guitar: with total freedom. And in early 1964, the 21-year-old took his new camera on perhaps the most momentous musical journey of the 20th century: The Beatles' invasion of America.

Hundreds of his photographs from that trip were recently rediscovered in McCartney's archive: "It was really nice," he said, "because I thought they were lost."

An exhibition of the images, collected in the book, "1964: Eyes of the Storm," originated at the National Portrait Gallery in London. The show is now on view at the Brooklyn Museum in New York.