Life is a miracle in itself, and its development is an unending wave of awe. We all know it starts with the fusion of two tiny cells, but how it transforms into a unique living individual is magical and nearly inconceivable. Every newborn child is proof that this life is infinitely diverse, yet it all starts in the same wondrous way. With the help of today's advanced technology, we can appreciate how life begins in the womb. Scroll through the stages of an embryo's development, starting at the moment of conception, aided by the detailed photographs by Lennart Nilsson, from his book A Child Is Born.
Here's where it all begins: the sperm enters the Fallopian tube.
At the end of its journey for survival, it approaches the egg. So close.
When there's a lucky winner, the egg is fertilized 12 to 24 hours after penetration. This is the beginning of the whole complicated process, which leads to a new human life. Did you know that the egg actually chooses the sperm? It's not just a race, the egg decides which sperm is allowed in.
The fertilized egg travels down the Fallopian tube, while multiplying into cells. It then enters the uterus and burrows into the uterine lining. From this point onward, the baby will start to form.
After 3 to 4 weeks: From a ball of rapidly multiplying cells, a baby starts to take shape.
After 5 to 6 weeks: Although the size of a lentil, the baby starts to form shapes of nostrils, a mouth and eyes on its face. Intestines and lungs also start to develop.
After 7 to 8 weeks: You can see a human-like embryo, which is well protected in the fetal sac. It is growing rapidly, and its little hands and feet start to show.
After 9 to 10 weeks: Still the size of a grape, but the basic human physiology is now in place. The embryonic tail has now disappeared and the embryo's eyelids are semi-shut. These eventually close completely.
By 10 weeks, the most critical portion of the baby's development is complete.
After 12 weeks: The baby now has tiny limbs with fine details, such as nails. It can now kick, stretch, bend its legs and hands, use its fingers to explore the world, and make suckling movements with its mouth. Soon, the baby's tiny fingers will have their own fingerprints.
After 18 weeks: The baby is now the size of a bell pepper. A lot more has started to function in its body, such as the kidneys and the facial muscles. Bones start to thicken and flexing of the limbs is possible.
After 20 weeks: Smell, vision, touch, taste and hearing have now kicked in, the digestive system can function and body movements slowly increase. The first hairs start to grow on the head.
After 6 to 7 months: Now looking more like a newborn, the baby can inhale and exhale amniotic fluid, preparing it for the first breath of air at birth. The eyesight develops further, the muscles and lungs get stronger, and the head grows.
After 36 weeks: The weight is increasing by around an ounce a day, the brain is maturing, and only the last preparations are left for it to be ready to start its life in the outside world, where so much awaits it.
See more of Lennart Nilsson's work on his website.