About 2,400 years ago a scientist called Hippocrates in ancient Greece studied the blood. He believed that certain diseases were caused by having too much blood in the body.

Up until about 100 years ago, doctors used leeches to suck the 'bad' blood from the patients! But since the invention of the microscope scientists have learnt much more about this amazing liquid.

See for yourself, on our website, how fantastic it is!