The Swedish photographer Lennart Nilsson, whose pictures of fetuses developing in the womb illustrated a 1965 book that was translated into several languages, has died. He was 94.

Nilsson died Saturday, his stepdaughter told Sweden's TT news agency. No cause of death was given.

Nilsson's photos of the developing fetal stages first appeared in Life magazine and eventually in the book "Ett barn blir till," or "A Child is Born."

He started as a freelance photographer in the 1940s but later experimented with photographic techniques to take extreme close-ups. By combining that with very thin endoscopes that became available in the mid-1960s, he was able to take the photos that made him famous.