The Journey of 4 Sisters Over 4 Decades 

This image signifies the endurance of sisterhood in particular. Nixon, who grew up a single child, says he has always been particularly intrigued by the sisterly unit, and it shows in these images. With each passing year, the sisters seem to present more of a united front. Earlier assertions of their individuality — the arms folded across the chest, the standing apart — give way to a literal leaning on one another, as if independence is no longer such a concern.

2014