What is Greece's National flag?

Answer 1

Nine stripes from top to bottom alternate blue [five stripes] and white [four stripes] resembling the sky and the sea or the greek words "Ελευθερία ή Θάνατος" [Freedom or Death] that during the Greek Independence war the Greeks used.

In the upper hoist site of the flag there is white cross that extends to the top five stripes and signifies the Greek Orthodox religion.

There is also another explanation for the nine stripes that they represent the nine muses