Millions of red blood cells are created in our bone marrow each second. Built with iron-rich haemoglobin, they are able to bind and transport oxygen to every single cell in the human body. Unlike other human cells, a red blood cell lacks a nucleus, giving them the flexibility to squeeze through the tiniest blood capillaries in the human body. However, this comes at a price. Without a nucleus, a red blood cell only survives for about 100 to 120 days before being sent to the liver to be destroyed. Follow their short-lived but crucial journey through the human body in the video!