Originally a god of thunderstorms whose consort was Zarpanit, it was later claimed that An and Enlil transferred their powers to him.  
His main temple, with a name meaning "the house of the exalted head," was the Esagila.  Originally a god of thunderstorms whose consort was Zarpanit, it was later claimed that An and Enlil transferred their powers to him.  Later also known as Bel, he in fact had 50 names.  He was given kingship over the universe and the other gods in the Enuma Elish for his defeat of both Kingu and Tiamat.  FTP, name this chief Babylonian god.
His main temple, with a name meaning "the house of the exalted head," was the Esagila.  
Marduk (accept Bel before it is mentioned)