-"Oh king, this head of fine gold is you and your kingdom!"
According to the God's Word, the great kingdom of Babylon, the "golden city" of ancient times (Isaiah 14:4), with its great King Nebuchadnezzar, was the head of gold.
That means he was the best & the first and the most important part.
Nebuchadenazzar was the best of these Empires because he proclaimed God as the most high God above all other gods ( see Daniel 2:47), & he commanded all of his people to reverence the Lord. (See Daniel 4:37.)
He later even got saved! (See Daniel 4:37)