Fetus, 18 weeks

When LIFE published Lennart Nilsson's photo essay "Drama if Life Before Birth" in 1965, the issue was so popular that it sold out within days. And for good reason. Nilsson's images publicly revealed for the first time what a developing fetus looks like, and in the process raised pointed new questions about when life begins. In the accompanying story, LIFE explained that all but one of the fetuses pictured were photographed outside the womb and had been removed--or aborted--"for variety of medical reasons." Nilsson had struck a deal with a hospital in Stockholm, whose doctors called him whenever a fetus was available to photograph. There, in a dedicated room with lights and lenses specially designed for the project, Nilsson arranged the fetuses so they appeared to be floating as if in the womb.