Blood vessels are responsible for transporting blood, oxygen and nutrients to different parts of the body. These vessels include the Arteries, Veins and Capillaries. Although capillaries are so tiny and microscopic, there are a lot of them. If these vessels were stretched out and placed end to end, they would reach a length of about 100,000 KM! That is how amazing our circulatory system is.
The circumference of the Earth at the equator is about 40,000 KM, so the blood vessels in one person, when wrapped around the earth, it can go around almost 2.5 times!