The main objective of the circulatory system is  transporting oxygenated (rich saturation of oxygen) blood around  the body. The de-oxygenated blood enters through the vena cava and  into the right atrium of the heart. It then goes to the right  ventricle, directly below the atrium.
Pyramid of the Sun. Less than half a mile south of the Pyramid of the Moon is the Pyramid of Sun. At a height of more than 200 feet (63 meters) and a base more than 730 feet (225 meters) long on each side, this pyramid is one of the largest structures created in the pre-Columbian New World. It would have been completed around 200 AD.
The largest and most famous of all the pyramids, the Great Pyramid at Giza, was built by Snefru's son, Khufu, known also as Cheops, the later Greek form of his name. The pyramid's base covered over 13 acres and its sides rose at an angle of 51 degrees 52 minutes and were over 755 feet long. It originally stood over 481 feet high; today it is 450 feet high. Scientists estimate that its stone blocks average over two tons apiece, with the largest weighing as much as fifteen tons each.