The largest artery in the human body is the aorta. The aorta originates from the left ventricle of the heart and carries oxygenated blood to various parts of the body. It is the main artery that distributes blood to the systemic circulation, supplying oxygen and nutrients to all organs and tissues. The aorta is approximately one inch (2.5 centimeters) in diameter and extends down from the heart, curving in an arch-like shape before descending through the chest and abdomen.