Monument at the Pass of Thermopylae [study]

This is a WIP - a study of the present monument to the Battle of Thermopylae. The battleground today is hard to discern since the pass no longer is bordered by the mountain and the sea, which hasa receded since the Battle. Xerxes would simply go around the Greek force since there would be plenty of room; whereas, they would have been forced through a narrow pass, made narrow by a mountain on one said and the sea on the other.