A Child is Born: Photographs of the foetus developing in the womb by Lennart Nilsson

When Lennart Nilsson's pictures of developing embryos were published in Life magazine in 1965, they caused a sensation. Within days, the entire print run of eight million had sold out. More than 40 years later, the photographs have lost none of their power

Five weeks. The embryo is approximately 9mm long. A face develops, with openings for the mouth, the nostrils and eyes

Eight weeks. The rapidly-growing embryo is well protected in the foetal sac

10 weeks. The eyelids are semi-shut. They will close completely in a few days

16 weeks. The foetus uses its hands to explore its own body and its surroundings...

The foetus can now grab and pull the long umbilical cord. The skeleton consists mainly of flexible cartridge. A network of blood vessels is visible through the thin skin

18 weeks: Approximately 14cm. The foetus can now perceive sounds from the outside world

20 weeks. Approximately 20cm. Woolly hair, known as lanugo, covers the entire head