In the summer of 1974, photographer Nicholas Nixon asked his wife, Bebe, to pose for a portrait with her three sisters, Heather, Mimi and Laurie. Unhappy with how the first effort turned out, they agreed to try again the following year. Feeling the power of sisterhood and the sense of unspoken stories the first two shots portrayed, Nicholas and the sisters made it an annual tradition. See how they grow and transform through the years.
All images: Nicholas Nixon