Robert Redford's childhood brush with polio inspired him to direct a movie about a building named after vaccine inventor Jonas Salk.
The Hollywood veteran has stepped behind the camera to take charge of a short 3D documentary which is part of a six-part series about iconic buildings called Cathedrals of Culture.
Redford's installment focuses on the Salk Institute for Biological Studies in San Diego, California, which was founded in 1960 by Jonas Salk, the scientist who developed the first polio vaccine, and Redford admits his own struggle with the disease, aged 11, inspired him to tackle the project.
He says, "From a personal standpoint I knew something about the building because I grew up in Los Angeles not far from that area... so I was around when that building was being built. Also, I was around when the polio epidemic was still a threat. You could get it. I had a mild case of it myself when I was 11 years old, and fortunately it was mild enough not to cause me any real damage. Polio was part of the picture, so when Jonas Salk invented the vaccine, it was just earth-shattering news."