I love art history, and one of my favorites is the Ziggurat from Ancient Mesopotamia. What Ziggurats are basically a huge ladder to heaven, as Mesopotamians believed that the closer you were to the sky, the closer you were to their god. Unlike Egyptian Pyramids that store relics; Ziggurats actually do not have anything inside. Ziggurats were made out of clay bricks and were often called, "White Temples". Most schematics that you look up, the top seems to be decorated with a blue color which is why blue is included here.