Ziggurats in the Fertile Crescent

Ziggurats evolved from early temple complexes in the fertile crescent. Some of these pyramid-like structure reach as high as 300 ft. 

The White Temple of Uruk (Erech in the old testament), dedicated to the Sumerian God An, lord of the heavens, is one of the earliest exaples and dates back to the late 3000s BCE

Mesopotamian ziggurats were built in series of three, five, or seven. They had narrow terraces with steps for climbing to the next levels. The seven terraces were said to correspond to the seven planetary heavens. 

The first level, according to Sumerian tradition, is linked with Saturn and was painted black. The second level was linked with with Jupiter and was painted white; the third was red and was linked with Mercury. The forth blue level was associated with Venus; the fifth is level of the ziggurats is lost to time; the sixth is Mars and yellow, and the seventh and final level was silver and was thought to represent the moon. 

Sacrifices were usually held at the top level of a ziggurat because they were seen as representation of the cosmic mountain at the center of the world. Ziggurats were seen as ladders between heaven and earth creating a passage way for mortals to ascend and gods to descend.