But as for me, this secret is not revealed to me for any wisdom that I have more than any living, but for their sakes that shall make known the interpretation to the king, and that thou mightest know the thoughts of thy heart. DANIEL 2:30

In Danial Chapter 2 we read

31 Thou, O king, sawest, and behold a great image. This great image, whose brightness was excellent, stood before thee; and the form thereof was terrible. 32 This image's
head was of fine gold,
his breast and his arms of silver,
his belly and his thighs of brass,
33 His legs of iron,
his feet part of iron and part of clay.

So what is so special about this statue, and how can we know what it is? Really it is just too easy. The book of Daniel lets us know exactly what it is. Lets look at the next few verses.

36 This is the dream; and we will tell the interpretation thereof before the king. 37 Thou, O king, art a king of kings: for the God of heaven hath given thee a kingdom, power, and strength, and glory. 38 And wheresoever the children of men dwell, the beasts of the field and the fowls of the heaven hath he given into thine hand, and hath made thee ruler over them all. Thou art this head of gold.

Here we have evidence that the first metal represents Nebuchadnezzar. In the Following verses we will see that each subsiquent metal, comprising the statue, represent Kingdoms. Therefore we know the Head of gold to represent not only wicked Nebuchadnezzar, but also his rotten kingdom Babylon.

39 And after thee shall arise another kingdom inferior to thee, and another third kingdom of brass, which shall bear rule over all the earth.

In 539 B.C. The Media & Persian empires conqured Babylon. "And after thee shall arise another kingdom inferior to thee,..."
In 331 B.C. The Medo-Persian Empire fell to the hand of Alexander the great and the Greek empire arose; which shall bear rule over all the earth.

40 And the fourth kingdom shall be strong as iron: forasmuch as iron breaketh in pieces and subdueth all things: and as iron that breaketh all these, shall it break in pieces and bruise.
IN 168 B.C. Rome chrushed the Grecian empire and ruled with a rod of iron for the next 644 YEARS!

41 And whereas thou sawest the feet and toes, part of potters' clay, and part of iron, the kingdom shall be divided; but there shall be in it of the strength of the iron, forasmuch as thou sawest the iron mixed with miry clay. 42 And as the toes of the feet were part of iron, and part of clay, so the kingdom shall be partly strong, and partly broken. 43 And whereas thou sawest iron mixed with miry clay, they shall mingle themselves with the seed of men: but they shall not cleave one to another, even as iron is not mixed with clay.

Now if you look in your history books you will find that ten Tribes or nation heads emerged within and arround Europe. They were:
Suevi(NW Spain)
Vandals(N. Africa)

Babylon (605-539 B.C.) Medo-Persia (539-331 B.C.) Greece (331-168 B.C.) Rome (168 B.C. - A.D. 476)