This photo series is incredibly interesting and a little scary. It all started when Nicolas Nixon decided to photograph his wife and her three sisters back in 1975. The shot was so good that the four sisters decided to make a tradition of it and posed in exactly the same position on a yearly basis for the next 36 years.
Watching these beautiful women age is fascinating. The full collection can be found in high-resolution quality in the book Nicholas Nixon: The Brown Sisters. Thirty-Three Years.