Pilgrimage took Annie Leibovitz to places that she could explore with no agenda. She wasn't on assignment. She chose the subjects simply because they meant something to her. The first place was Emily Dickinson's house in Amherst, Massachusetts, which Leibovitz visited with a small digital camera. A few months later, she went with her three young children to Niagara Falls. 'That's when I started making lists,' she says. She added the houses of Virginia Woolf and Darwin in the English countryside and Freud's final home, in London, but most of the places on the lists were American. The work became more ambitious as Leibovitz discovered that she wanted to photograph objects as well as rooms and landscapes. She began to use more sophisticated cameras and a tripod and to travel with an assistant, but the project remained personal. Leibovitz went to Concord to photograph the site of Thoreau's cabin at Walden Pond. Once she got there, she was drawn into the wider world of the Concord writers